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 •
CVE-2020-1313 CVSS v3 Base Score: 7.8
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
  • Attacker Value
    High
  • Exploitability
    High
Common in enterpriseEasy to weaponizeGives privileged accessVulnerable in default configurationAuthenticated
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

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CVSS V3 Severity and Metrics
Base Score:
7.8 High
Impact Score:
5.9
Exploitability Score:
1.8
Vector:
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Attack Vector (AV):
Local
Attack Complexity (AC):
Low
Privileges Required (PR):
None
User Interaction (UI):
Required
Scope (S):
Unchanged
Confidentiality (C):
High
Integrity (I):
High
Availability (A):
High

General Information

Offensive Application
Unknown
Utility Class
Unknown
Ports
Unknown
OS
Unknown
Vulnerable Versions
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
Prerequisites
Unknown
Discovered By
Unknown
PoC Author
Unknown
Metasploit Module
exploit/windows/local/cve_2020_1313_system_orchestrator
Reporter
Unknown

Vendors

  • microsoft

Products

  • windows 10 1903,
  • windows 10 1909,
  • windows 10 2004,
  • windows server 2016 1903,
  • windows server 2016 1909,
  • windows server 2016 2004

Additional Info

Authenticated
Unknown
Exploitable
Unknown
Reliability
Unknown
Stability
Unknown
Available Mitigations
Unknown
Shelf Life
Unknown
Userbase/Installbase
Unknown
Patch Effectiveness
Unknown
Technical Analysis