Agent impersonation via leaked registration HMAC
Published Aug 25, 2023 · Updated Nov 20, 2025
Authorization bypass in Red Hat Enterprise Linux 9 Keylime allows attackers to impersonate monitored agents via public registration endpoints. On failed activation, the registrar returns an HTTP error containing the expected HMAC auth_tag, which an attacker can replay in a second activation request. Registrar access, a valid EK certificate and EK, and later addition of the fake agent to the verifier are required to conceal a monitored machine's true status.
Summary
What happened
Authorization bypass in Red Hat Enterprise Linux 9 Keylime allows attackers to impersonate monitored agents via public registration endpoints. On failed activation, the registrar returns an HTTP error containing the expected HMAC auth_tag, which an attacker can replay in a second activation request. Registrar access, a valid EK certificate and EK, and later addition of the fake agent to the verifier are required to conceal a monitored machine's true status.
The record
- CVE
- CVE-2023-38201
- Published
- Aug 25, 2023
- Updated
- Nov 20, 2025
- Vendor
- Red Hat
- Product
- Red Hat Enterprise Linux 9
- Classifications
- CWE-639, T1562.001
- Attack vector
- adjacent
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 25, 2023CVE publishedPublication date reported by the CVE source.
- Nov 20, 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?
Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.
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
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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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