Attacker Value
High
(1 user assessed)
Exploitability
High
(1 user assessed)
User Interaction
Required
Privileges Required
None
Attack Vector
Local
1

CVE-2020-1313

Disclosure Date: June 09, 2020
Add MITRE ATT&CK tactics and techniques that apply to this CVE.
Privilege Escalation
Techniques
Validation
Validated

Description

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’.

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4
Ratings
Technical Analysis

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

General Information

Vendors

  • Microsoft

Products

  • Windows 10 Version 1909 for 32-bit Systems,
  • Windows 10 Version 1909 for x64-based Systems,
  • Windows 10 Version 1909 for ARM64-based Systems,
  • Windows Server, version 1909 (Server Core installation),
  • Windows 10 Version 1903 for 32-bit Systems,
  • Windows 10 Version 1903 for x64-based Systems,
  • Windows 10 Version 1903 for ARM64-based Systems,
  • Windows Server, version 1903 (Server Core installation),
  • Windows Server, version 2004 (Server Core installation),
  • Windows 10 Version 2004 for 32-bit Systems,
  • Windows 10 Version 2004 for ARM64-based Systems,
  • Windows 10 Version 2004 for x64-based Systems

Additional Info

Technical Analysis