Authentication bypass via unchecked Kerberos target SPN
Published Jun 8, 2021 · Updated Aug 3, 2024
Security feature bypass in Microsoft Windows Kerberos allows remote attackers to authenticate to an arbitrary service principal name. Kerberos accepts a security buffer that sets a ticket's target SPN without enforcing LSASS's AppContainer enterprise-authentication capability check. Exploitation requires code executing inside an AppContainer and exposes services reachable through the chosen SPN under the container user's credentials.
Summary
What happened
Security feature bypass in Microsoft Windows Kerberos allows remote attackers to authenticate to an arbitrary service principal name. Kerberos accepts a security buffer that sets a ticket's target SPN without enforcing LSASS's AppContainer enterprise-authentication capability check. Exploitation requires code executing inside an AppContainer and exposes services reachable through the chosen SPN under the container user's credentials.
The record
- CVE
- CVE-2021-31962
- Published
- Jun 8, 2021
- Updated
- Aug 3, 2024
- Vendor
- Microsoft
- Product
- Windows 10 Version 1507
- Classifications
- Unavailable
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jun 8, 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 <10.0.10240.18967
What conditions does exploitation require?
What is affected?
Published CVSS scores
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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
No sourced classifications are available.
Public exploit references
- Windows Kerberos AppContainer Enterprise Authentication Capability Bypassproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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