Privileged Event Log access via relayed NTLM authentication
Published Jun 8, 2021 · Updated Aug 3, 2024
Authentication bypass in Microsoft Windows allows remote attackers to obtain privileged Event Log service access through NTLM relay. RpcInterfaceSecurityCallback accepted connection-level MSRPC authentication without requiring packet integrity, allowing relayed credentials to open the service. A victim must authenticate to an attacker-controlled endpoint or through a man-in-the-middle position; access can disclose logs, overwrite files, or exhaust disk space.
Summary
What happened
Authentication bypass in Microsoft Windows allows remote attackers to obtain privileged Event Log service access through NTLM relay. RpcInterfaceSecurityCallback accepted connection-level MSRPC authentication without requiring packet integrity, allowing relayed credentials to open the service. A victim must authenticate to an attacker-controlled endpoint or through a man-in-the-middle position; access can disclose logs, overwrite files, or exhaust disk space.
The record
- CVE
- CVE-2021-31958
- Published
- Jun 8, 2021
- Updated
- Aug 3, 2024
- Vendor
- Microsoft
- Product
- Windows 10 Version 1507
- Classifications
- CWE-294, T1187
- 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
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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