ThievingFox - Remotely Retrieving Credentials From Password Managers And Windows Utilities

ThievingFox is a collection of post-exploitation tools to gather credentials from various password managers and windows utilities. Each module leverages a specific method of injecting into the target process, and then hooks internals functions to gather crendentials.

The accompanying blog post can be found here

Installation

Linux

Rustup must be installed, follow the instructions available here : https://rustup.rs/

The mingw-w64 package must be installed. On Debian, this can be done using :

apt install mingw-w64

Both x86 and x86_64 windows targets must be installed for Rust:

rustup target add x86_64-pc-windows-gnu
rustup target add i686-pc-windows-gnu

Mono and Nuget must also be installed, instructions are available here : https://www.mono-project.com/download/stable/#download-lin

After adding Mono repositories, Nuget can be installed using apt :

apt install nuget

Finally, python dependancies must be installed :

pip install -r client/requirements.txt

ThievingFox works with python >= 3.11.

Windows

Rustup must be installed, follow the instructions available here : https://rustup.rs/

Both x86 and x86_64 windows targets must be installed for Rust:

rustup target add x86_64-pc-windows-msvc
rustup target add i686-pc-windows-msvc

.NET development environment must also be installed. From Visual Studio, navigate to Tools > Get Tools And Features > Install ".NET desktop development"

Finally, python dependancies must be installed :

pip install -r client/requirements.txt

ThievingFox works with python >= 3.11

NOTE : On a Windows host, in order to use the KeePass module, msbuild must be available in the PATH. This can be achieved by running the client from within a Visual Studio Developper Powershell (Tools > Command Line > Developper Powershell)

Targets

All modules have been tested on the following Windows versions :

[!CAUTION] Modules have not been tested on other version, and are expected to not work.

Usage

[!CAUTION] Although I tried to ensure that these tools do not impact the stability of the targeted applications, inline hooking and library injection are unsafe and this might result in a crash, or the application being unstable. If that were the case, using the cleanup module on the target should be enough to ensure that the next time the application is launched, no injection/hooking is performed.

ThievingFox contains 3 main modules : poison, cleanup and collect.

Poison

For each application specified in the command line parameters, the poison module retrieves the original library that is going to be hijacked (for COM hijacking and DLL proxying), compiles a library that has matches the properties of the original DLL, uploads it to the server, and modify the registry if needed to perform COM hijacking.

To speed up the process of compilation of all libraries, a cache is maintained in client/cache/.

--mstsc, --rdcman, and --mobaxterm have a specific option, respectively --mstsc-poison-hkcr, --rdcman-poison-hkcr, and --mobaxterm-poison-hkcr. If one of these options is specified, the COM hijacking will replace the registry key in the HKCR hive, meaning all users will be impacted. By default, only all currently logged in users are impacted (all users that have a HKCU hive).

--keepass and --keepassxc have specific options, --keepass-path, --keepass-share, and --keepassxc-path, --keepassxc-share, to specify where these applications are installed, if it's not the default installation path. This is not required for other applications, since COM hijacking is used.

The KeePass modules requires the Visual C++ Redistributable to be installed on the target.

Multiple applications can be specified at once, or, the --all flag can be used to target all applications.

[!IMPORTANT] Remember to clean the cache if you ever change the --tempdir parameter, since the directory name is embedded inside native DLLs.

$ python3 client/ThievingFox.py poison -h
usage: ThievingFox.py poison [-h] [-hashes HASHES] [-aesKey AESKEY] [-k] [-dc-ip DC_IP] [-no-pass] [--tempdir TEMPDIR] [--keepass] [--keepass-path KEEPASS_PATH]
                             [--keepass-share KEEPASS_SHARE] [--keepassxc] [--keepassxc-path KEEPASSXC_PATH] [--keepassxc-share KEEPASSXC_SHARE] [--mstsc] [--mstsc-poison-hkcr]
                             [--consent] [--logonui] [--rdcman] [--rdcman-poison-hkcr] [--mobaxterm] [--mobaxterm-poison-hkcr] [--all]
                             target

positional arguments:
  target                Target machine or range [domain/]username[:password]@<IP or FQDN>[/CIDR]

options:
  -h, --help            show this help message and exit
  -hashes HASHES, --hashes HASHES
                        LM:NT hash
  -aesKey AESKEY, --aesKey AESKEY
                        AES key to use for Kerberos Authentication
  -k                       Use kerberos authentication. For LogonUI, mstsc and consent modules, an anonymous NTLM authentication is performed, to retrieve the OS version.
  -dc-ip DC_IP, --dc-ip DC_IP
                        IP Address of the domain controller
  -no-pass, --no-pass   Do not prompt for password
  --tempdir TEMPDIR     The name of the temporary directory to use for DLLs and output (Default: ThievingFox)
  --keepass             Try to poison KeePass.exe
  --keepass-path KEEPASS_PATH
                        The path where KeePass is installed, without the share name (Default: /Program Files/KeePass Password Safe 2/)
  --keepass-share KEEPASS_SHARE
                        The share on which KeePass is installed (Default: c$)
  --keepassxc           Try to poison KeePassXC.exe
  --keepassxc-path KEEPASSXC_PATH
                        The path where KeePassXC is installed, without the share name (Default: /Program Files/KeePassXC/)
  --ke   epassxc-share KEEPASSXC_SHARE
                        The share on which KeePassXC is installed (Default: c$)
  --mstsc               Try to poison mstsc.exe
  --mstsc-poison-hkcr   Instead of poisonning all currently logged in users' HKCU hives, poison the HKCR hive for mstsc, which will also work for user that are currently not
                        logged in (Default: False)
  --consent             Try to poison Consent.exe
  --logonui             Try to poison LogonUI.exe
  --rdcman              Try to poison RDCMan.exe
  --rdcman-poison-hkcr  Instead of poisonning all currently logged in users' HKCU hives, poison the HKCR hive for RDCMan, which will also work for user that are currently not
                        logged in (Default: False)
  --mobaxterm           Try to poison MobaXTerm.exe
  --mobaxterm-poison-hkcr
                        Instead of poisonning all currently logged in users' HKCU hives, poison the HKCR hive for    MobaXTerm, which will also work for user that are currently not
                        logged in (Default: False)
  --all                 Try to poison all applications

Cleanup

For each application specified in the command line parameters, the cleanup first removes poisonning artifacts that force the target application to load the hooking library. Then, it tries to delete the library that were uploaded to the remote host.

For applications that support poisonning of both HKCU and HKCR hives, both are cleaned up regardless.

Multiple applications can be specified at once, or, the --all flag can be used to cleanup all applications.

It does not clean extracted credentials on the remote host.

[!IMPORTANT] If the targeted application is in use while the cleanup module is ran, the DLL that are dropped on the target cannot be deleted. Nonetheless, the cleanup module will revert the configuration that enables the injection, which should ensure that the next time the application is launched, no injection is performed. Files that cannot be deleted by ThievingFox are logged.

$ python3 client/ThievingFox.py cleanup -h
usage: ThievingFox.py cleanup [-h] [-hashes HASHES] [-aesKey AESKEY] [-k] [-dc-ip DC_IP] [-no-pass] [--tempdir TEMPDIR] [--keepass] [--keepass-share KEEPASS_SHARE]
                              [--keepass-path KEEPASS_PATH] [--keepassxc] [--keepassxc-path KEEPASSXC_PATH] [--keepassxc-share KEEPASSXC_SHARE] [--mstsc] [--consent] [--logonui]
                              [--rdcman] [--mobaxterm] [--all]
                              target

positional arguments:
  target                Target machine or range [domain/]username[:password]@<IP or FQDN>[/CIDR]

options:
  -h, --help            show this help message and exit
  -hashes HASHES, --hashes HASHES
                        LM:NT hash
  -aesKey AESKEY, --aesKey AESKEY
                        AES key to use for Kerberos Authentication
  -k                    Use kerberos authentication. For LogonUI, mstsc and cons   ent modules, an anonymous NTLM authentication is performed, to retrieve the OS version.
  -dc-ip DC_IP, --dc-ip DC_IP
                        IP Address of the domain controller
  -no-pass, --no-pass   Do not prompt for password
  --tempdir TEMPDIR     The name of the temporary directory to use for DLLs and output (Default: ThievingFox)
  --keepass             Try to cleanup all poisonning artifacts related to KeePass.exe
  --keepass-share KEEPASS_SHARE
                        The share on which KeePass is installed (Default: c$)
  --keepass-path KEEPASS_PATH
                        The path where KeePass is installed, without the share name (Default: /Program Files/KeePass Password Safe 2/)
  --keepassxc           Try to cleanup all poisonning artifacts related to KeePassXC.exe
  --keepassxc-path KEEPASSXC_PATH
                        The path where KeePassXC is installed, without the share name (Default: /Program Files/KeePassXC/)
  --keepassxc-share KEEPASSXC_SHARE
                        The share on which KeePassXC is installed (Default: c$)
  --mstsc               Try to cleanup all poisonning artifacts related to mstsc.exe
  --consent             Try to cleanup all poisonning artifacts related to Consent.exe
  --logonui             Try to cleanup all poisonning artifacts related to LogonUI.exe
  --rdcman              Try to cleanup all poisonning artifacts related to RDCMan.exe
  --mobaxterm           Try to cleanup all poisonning artifacts related to MobaXTerm.exe
  --all                 Try to cleanup all poisonning artifacts related to all applications

Collect

For each application specified on the command line parameters, the collect module retrieves output files on the remote host stored inside C:\Windows\Temp\<tempdir> corresponding to the application, and decrypts them. The files are deleted from the remote host, and retrieved data is stored in client/ouput/.

Multiple applications can be specified at once, or, the --all flag can be used to collect logs from all applications.

$ python3 client/ThievingFox.py collect -h
usage: ThievingFox.py collect [-h] [-hashes HASHES] [-aesKey AESKEY] [-k] [-dc-ip DC_IP] [-no-pass] [--tempdir TEMPDIR] [--keepass] [--keepassxc] [--mstsc] [--consent]
                              [--logonui] [--rdcman] [--mobaxterm] [--all]
                              target

positional arguments:
  target                Target machine or range [domain/]username[:password]@<IP or FQDN>[/CIDR]

options:
  -h, --help            show this help message and exit
  -hashes HASHES, --hashes HASHES
                        LM:NT hash
  -aesKey AESKEY, --aesKey AESKEY
                        AES key to use for Kerberos Authentication
  -k                    Use kerberos authentication. For LogonUI, mstsc and consent modules, an anonymous NTLM authentication is performed, to retrieve the OS version.
  -dc-ip DC_IP, --dc-ip DC_IP
                        IP Address of th   e domain controller
  -no-pass, --no-pass   Do not prompt for password
  --tempdir TEMPDIR     The name of the temporary directory to use for DLLs and output (Default: ThievingFox)
  --keepass             Collect KeePass.exe logs
  --keepassxc           Collect KeePassXC.exe logs
  --mstsc               Collect mstsc.exe logs
  --consent             Collect Consent.exe logs
  --logonui             Collect LogonUI.exe logs
  --rdcman              Collect RDCMan.exe logs
  --mobaxterm           Collect MobaXTerm.exe logs
  --all                 Collect logs from all applications

KRBUACBypass - UAC Bypass By Abusing Kerberos Tickets

This POC is inspired by James Forshaw (@tiraniddo) shared at BlackHat USA 2022 titled “Taking Kerberos To The Next Level ” topic, he shared a Demo of abusing Kerberos tickets to achieve UAC bypass. By adding a KERB-AD-RESTRICTION-ENTRY to the service ticket, but filling in a fake MachineID, we can easily bypass UAC and gain SYSTEM privileges by accessing the SCM to create a system service. James Forshaw explained the rationale behind this in a blog post called "Bypassing UAC in the most Complex Way Possible!", which got me very interested. Although he didn't provide the full exploit code, I built a POC based on Rubeus. As a C# toolset for raw Kerberos interaction and ticket abuse, Rubeus provides an easy interface that allows us to easily initiate Kerberos requests and manipulate Kerberos tickets.

You can see related articles about KRBUACBypass in my blog "Revisiting a UAC Bypass By Abusing Kerberos Tickets", including the background principle and how it is implemented. As said in the article, this article was inspired by @tiraniddo's "Taking Kerberos To The Next Level" (I would not have done it without his sharing) and I just implemented it as a tool before I graduated from college.

Tgtdeleg Trick

We cannot manually generate a TGT as we do not have and do not have access to the current user's credentials. However, Benjamin Delpy (@gentilkiwi) in his Kekeo A trick (tgtdeleg) was added that allows you to abuse unconstrained delegation to obtain a local TGT with a session key.

Tgtdeleg abuses the Kerberos GSS-API to obtain available TGTs for the current user without obtaining elevated privileges on the host. This method uses the AcquireCredentialsHandle function to obtain the Kerberos security credentials handle for the current user, and calls the InitializeSecurityContext function for HOST/DC.domain.com using the ISC_REQ_DELEGATE flag and the target SPN to prepare the pseudo-delegation context to send to the domain controller. This causes the KRB_AP-REQ in the GSS-API output to include the KRB_CRED in the Authenticator Checksum. The service ticket's session key is then extracted from the local Kerberos cache and used to decrypt the KRB_CRED in the Authenticator to obtain a usable TGT. The Rubeus toolset also incorporates this technique. For details, please refer to “Rubeus – Now With More Kekeo”.

With this TGT, we can generate our own service ticket, and the feasible operation process is as follows:

1. Use the Tgtdeleg trick to get the user's TGT.
2. Use the TGT to request the KDC to generate a new service ticket for the local computer. Add a KERB-AD-RESTRICTION-ENTRY, but fill in a fake MachineID.
3. Submit the service ticket into the cache.

Krbscm

Once you have a service ticket, you can use Kerberos authentication to access Service Control Manager (SCM) Named Pipes or TCP via HOST/HOSTNAME or RPC/HOSTNAME SPN. Note that SCM's Win32 API always uses Negotiate authentication. James Forshaw created a simple POC: SCMUACBypass.cpp, through the two APIs HOOK AcquireCredentialsHandle and InitializeSecurityContextW, the name of the authentication package called by SCM (pszPack age ) to Kerberos to enable the SCM to use Kerberos when authenticating locally.

Let’s see it in action

Now let's take a look at the running effect, as shown in the figure below. First request a ticket for the HOST service of the current server through the asktgs function, and then create a system service through krbscm to gain the SYSTEM privilege.

KRBUACBypass.exe asktgs
KRBUACBypass.exe krbscm