CVE-2020-1313

An elevation of privilege vulnerability exists when the Windows Update Orchestrator Service improperly handles file operations, aka ‘Windows Update Orchestrator Service Elevation of Privilege Vulnerability’.

Recent assessments:

bwatters-r7 at September 18, 2020 9:01pm UTC reported:

This vulnerability exists in the Windows Update Orchestrator service. A scheduling API call, ScheduleWork does not validate the caller’s permissions, but will schedule a task to be run as SYSTEM. It is present on all version of Windows 10 and Windows Server Core.
One protection that exists is that the binary scheduled for launch must be signed by Microsoft. Unfortunately, it appears you can bypass this restriction by passing an unsigned binary into the cmd.exe signed Windows binary as a parameter. The only other difficulty is that an attacker cannot schedule the execution, but the schedule is determined by the service, and will take place at a time when the scheduler believes the computer will be idle.
Mitigations to this might include checking all scheduled jobs for any files not in the system32 directory. The specific registry key for the jobs is located here:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate\Orchestrator\UScheduler

More information and PoC code located here: <https://github.com/irsl/CVE-2020-1313&gt;

Assessed Attacker Value: 4
Assessed Attacker Value: 4Assessed Attacker Value: 4