module

Lexmark Driver Privilege Escalation

Disclosed
2021-07-15
Created
2021-08-12

Description

Various Lexmark Universal Printer drivers as listed at advisory TE953
allow low-privileged authenicated users to elevate their privileges to
SYSTEM on affected Windows systems by modifying the XML file at
C:\ProgramData\\Universal Color Laser.gdl
to replace the DLL path to unires.dll with a malicious DLL path.

When C:\Windows\System32\Printing_Admin_Scripts\en-US\prnmngr.vbs is
then used to add the printer to the affected system, PrintIsolationHost.exe,
a Windows process running as NT AUTHORITY\SYSTEM, will inspect the
C:\ProgramData\\Universal Color Laser.gdl file and will
load the malicious DLL from the path specified in the file. This which will
result in the malicious DLL executing as NT AUTHORITY\SYSTEM.

Once this module is finished, it will use the prnmngr.vbs script
to remove the printer it added.

Authors

Jacob Baines
Shelby Pace
Grant Willcox

Platform

Windows

Architectures

x86, x64

Module Options

To display the available options, load the module within the Metasploit console and run the commands ‘show options’ or ‘show advanced’:


msf > use exploit/windows/local/lexmark_driver_privesc
msf exploit(lexmark_driver_privesc) > show targets
...targets...
msf exploit(lexmark_driver_privesc) > set TARGET < target-id >
msf exploit(lexmark_driver_privesc) > show options
...show and set options...
msf exploit(lexmark_driver_privesc) > exploit

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