Local privilege escalation via temporary-file race
Published Feb 11, 2020 · Updated Aug 4, 2024
Elevation of privilege in Microsoft Windows Error Reporting allows local users to gain SYSTEM privileges by racing temporary-file operations. WerSvc creates a predictable WERFFFF.tmp in a directory writable by authenticated users, closes its handle, then later writes to or deletes the path without preventing replacement by filesystem links. A medium-integrity user must win a timing race and redirect the path through junctions and object-manager symbolic links, enabling SYSTEM-level deletion or corruption of protected files.
Summary
What happened
Elevation of privilege in Microsoft Windows Error Reporting allows local users to gain SYSTEM privileges by racing temporary-file operations. WerSvc creates a predictable WERFFFF.tmp in a directory writable by authenticated users, closes its handle, then later writes to or deletes the path without preventing replacement by filesystem links. A medium-integrity user must win a timing race and redirect the path through junctions and object-manager symbolic links, enabling SYSTEM-level deletion or corruption of protected files.
The record
- CVE
- CVE-2020-0754
- Published
- Feb 11, 2020
- Updated
- Aug 4, 2024
- Vendor
- Microsoft
- Product
- Windows 10 Version 1909
- Classifications
- T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Feb 11, 2020CVE publishedPublication date reported by the CVE source.
- Aug 4, 2024Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=unspecified
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- WERReport-CVE-2020-0754 proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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