module

Microsoft Windows ALPC Task Scheduler Local Privilege Elevation

Disclosed
Aug 27, 2018
Created
Mar 19, 2019

Description

On vulnerable versions of Windows the alpc endpoint method SchRpcSetSecurity implemented
by the task scheduler service can be used to write arbitrary DACLs to `.job` files located
in `c:\windows\tasks` because the scheduler does not use impersonation when checking this
location. Since users can create files in the `c:\windows\tasks` folder, a hardlink can be
created to a file the user has read access to. After creating a hardlink, the vulnerability
can be triggered to set the DACL on the linked file.

WARNING:
The PrintConfig.dll (%windir%\system32\driverstor\filerepository\prnms003*) on the target host
will be overwritten when the exploit runs.

This module has been tested against Windows 10 Pro x64.

Authors

SandboxEscaper
bwatters-r7
asoto-r7
Jacob Robles

Platform

Windows

Architectures

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/alpc_taskscheduler
msf exploit(alpc_taskscheduler) > show targets
...targets...
msf exploit(alpc_taskscheduler) > set TARGET < target-id >
msf exploit(alpc_taskscheduler) > show options
...show and set options...
msf exploit(alpc_taskscheduler) > exploit

Title
Rapid7 Labs

2026 Global Threat Landscape Report

The predictive window has collapsed. Exploitation follows disclosure in days. See how attackers are accelerating and how to stay ahead.