Authentication-policy bypass via unenforced AS-REQ silo checks
Published Mar 12, 2024 · Updated May 3, 2025
Improper authentication in Microsoft Windows Server allows remote authenticated users to bypass Active Directory authentication policies. The Key Distribution Center omits authentication-silo checks when processing AS-REQs for service principals other than krbtgt, although those checks already apply to TGS requests. Exploitation requires a low-privilege domain account and specially formed network authentication traffic; successful requests circumvent configured account restrictions and expose protected domain resources.
Summary
What happened
Improper authentication in Microsoft Windows Server allows remote authenticated users to bypass Active Directory authentication policies. The Key Distribution Center omits authentication-silo checks when processing AS-REQs for service principals other than krbtgt, although those checks already apply to TGS requests. Exploitation requires a low-privilege domain account and specially formed network authentication traffic; successful requests circumvent configured account restrictions and expose protected domain resources.
The record
- CVE
- CVE-2024-21427
- Published
- Mar 12, 2024
- Updated
- May 3, 2025
- Vendor
- Microsoft
- Product
- Windows Server 2019
- Classifications
- CWE-287
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Mar 12, 2024CVE publishedPublication date reported by the CVE source.
- May 3, 2025Record 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=10.0.17763.0 <10.0.17763.5696
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What is affected?
Published CVSS scores
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Attacks
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Weakness, pattern, technique
Public exploit references
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Technologies
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Your stack
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