11 KiB
Privilege Escalation Abusing Tokens
Tokens
If you don't know what are Windows Access Tokens read this page before continuing:
{% page-ref page="access-tokens.md" %}
Maybe you could be able to escalate privileges abusing the tokens you already have
SeImpersonatePrivilege 3.1.1
Any process holding this privilege can impersonate but not create any token for which it is able to gethandle. You can get a privileged token from a Windows service DCOM making it perform an NTLM authentication against the exploit, then execute a process as SYSTEM. Exploit it with juicy-potato, RogueWinRM needs winrm enabled, SweetPotato, PrintSpoofer.
SeAssignPrimaryPrivilege 3.1.2
It is very similar to SeImpersonatePrivilege, it will use the same method to get a privileged token.
Then, this privilege allows to assign a primary token to a new/suspended process. With the privileged impersonation token you can derivate a primary token DuplicateTokenEx.
With the token, you can create a new process with 'CreateProcessAsUser' or create a process suspended and set the token in general, you cannot modify the primary token of a running process.
SeTcbPrivilege 3.1.3
If you have enabled this token you can use KERB_S4U_LOGON to get an impersonation token for any other user without knowing the credentials, add an arbitrary group admins to the token, set the integrity level of the token to "medium", and assign this token to the current thread SetThreadToken.
SeBackupPrivilege 3.1.4
This privilege causes the system to grant all read access control to any file only read.
Use it to read the password hashes of local Administrator accounts from the registry and then use "psexec" or "wmicexec" with the hash PTH.
This attack won't work if the Local Administrator is disabled, or if it is configured that a Local Admin isn't admin if he is connected remotely.
You can abuse this privilege with: https://github.com/Hackplayers/PsCabesha-tools/blob/master/Privesc/Acl-FullControl.ps1 or with https://github.com/giuliano108/SeBackupPrivilege/tree/master/SeBackupPrivilegeCmdLets/bin/Debug
SeRestorePrivilege 3.1.5
Write access control to any file on the system, regardless of the files ACL.
You can modify services, DLL Hijacking, set debugger (Image File Execution Options)… A lot of options to escalate.
SeCreateTokenPrivilege 3.1.6
This token can be used as EoP method only if the user can impersonate tokens even without SeImpersonatePrivilege.
In a possible scenario, a user can impersonate the token if it is for the same user and the integrity level is less or equal to the current process integrity level.
In this case, the user could create an impersonation token and add to it a privileged group SID.
SeLoadDriverPrivilege 3.1.7
Load and unload device drivers.
You need to create an entry in the registry with values for ImagePath and Type.
As you don't have access to write to HKLM, you have to use HKCU. But HKCU doesn't mean anything for the kernel, the way to guide the kernel here and use the expected path for a driver config is to use the path: "\Registry\User\S-1-5-21-582075628-3447520101-2530640108-1003\System\CurrentControlSet\Services\DriverName" the ID is the **RID** of the current user.
So, you have to create all that path inside HKCU and set the ImagePath path to the binary that is going to be executed and Type SERVICE\_KERNEL\_DRIVER 0x00000001.
Learn how to exploit it here.****
SeTakeOwnershipPrivilege 3.1.8
This privilege is very similar to SeRestorePrivilege.
It allows a process to “take ownership of an object without being granted discretionary access” by granting the WRITE_OWNER access right.
First, you have to take ownership of the registry key that you are going to write on and modify the DACL so you can write on it.
SeDebugPrivilege 3.1.9
It allows the holder to debug another process, this includes reading and writing to that process' memory.
There are a lot of various memory injection strategies that can be used with this privilege that evade a majority of AV/HIPS solutions.
Check privileges
whoami /priv
The tokens that appear as Disabled can be enable, you you actually can abuse Enabled and Disabled tokens.
Table
Full token privileges cheatsheet at https://github.com/gtworek/Priv2Admin, summary below will only list direct ways to exploit the privilege to obtain an admin session or read sensitive files.
| Privilege | Impact | Tool | Execution path | Remarks |
|---|---|---|---|---|
SeAssignPrimaryToken
|
Admin | 3rd party tool | "It would allow a user to impersonate tokens and privesc to nt system using tools such as potato.exe, rottenpotato.exe and juicypotato.exe" | Thank you Aurélien Chalot for the update. I will try to re-phrase it to something more recipe-like soon. |
SeBackup
|
Threat | Built-in commands | Read sensitve files with robocopy /b
|
- May be more interesting if you can read %WINDIR%\MEMORY.DMP
- SeBackupPrivilege (and robocopy) is not helpful when it comes
to open files.
- Robocopy requires both SeBackup and SeRestore to work with /b parameter. |
SeCreateToken
|
Admin | 3rd party tool | Create arbitrary token including local admin rights with NtCreateToken. |
|
SeDebug
|
Admin | PowerShell | Duplicate the lsass.exe token. |
Script to be found at FuzzySecurity |
SeLoadDriver
|
Admin | 3rd party tool | 1. Load buggy kernel driver such as szkg64.sys
2. Exploit the driver vulnerability Alternatively, the privilege may be used to unload security-related drivers with ftlMC builtin command. i.e.: fltMC sysmondrv
|
1. The szkg64 vulnerability is listed as CVE-2018-15732
2. The szkg64 exploit code was
created by Parvez Anwar
|
SeRestore
|
Admin | PowerShell | 1. Launch PowerShell/ISE with the SeRestore privilege present.
2. Enable the privilege with Enable-SeRestorePrivilege). 3. Rename utilman.exe to utilman.old 4. Rename cmd.exe to utilman.exe 5. Lock the console and press Win+U |
Attack may be detected by some AV software. Alternative method relies on replacing service binaries stored in "Program Files" using the same privilege |
SeTakeOwnership
|
Admin | Built-in commands | 1. takeown.exe /f "%windir%\system32"
2. icalcs.exe "%windir%\system32" /grant "%username%":F
3. Rename cmd.exe to utilman.exe 4. Lock the console and press Win+U |
Attack may be detected by some AV software. Alternative method relies on replacing service binaries stored in "Program Files" using the same privilege. |
SeTcb
|
Admin | 3rd party tool |
Manipulate tokens to have local admin rights included. May require SeImpersonate. To be verified. |
Reference
- Take a look to this table defining Windows tokens: https://github.com/gtworek/Priv2Admin
- Take a look to this paper about privesc with tokens.