Local privilege escalation via case-sensitive junction bypass
Published Apr 13, 2021 · Updated Aug 3, 2024
Privilege escalation in Microsoft Diagnostics Hub Standard Collector Service allows local users to delete arbitrary protected files. DiagnosticsHub.StandardCollector.Runtime.dll compares a resolved scratch path with untrusted input using case-insensitive wcsnicmp, allowing a case-sensitive NTFS directory and junction swap to redirect recursive deletion. A low-privileged local account can reach the DCOM class; exploitation requires per-directory case sensitivity, available through WSL, Docker Desktop, or explicit configuration.
Summary
What happened
Privilege escalation in Microsoft Diagnostics Hub Standard Collector Service allows local users to delete arbitrary protected files. DiagnosticsHub.StandardCollector.Runtime.dll compares a resolved scratch path with untrusted input using case-insensitive wcsnicmp, allowing a case-sensitive NTFS directory and junction swap to redirect recursive deletion. A low-privileged local account can reach the DCOM class; exploitation requires per-directory case sensitivity, available through WSL, Docker Desktop, or explicit configuration.
The record
- CVE
- CVE-2021-28321
- Published
- Apr 13, 2021
- Updated
- Aug 3, 2024
- Vendor
- Microsoft
- Product
- Windows Server 2019
- Classifications
- CWE-59, T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Apr 13, 2021CVE publishedPublication date reported by the CVE source.
- Aug 3, 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=10.0.0 <publication
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
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
- Microsoft DiagHub case-sensitivity EoP proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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