CVE-2025-24032
PAM-PKCS#11 vulnerable to authentication bypass with default value for `cert_policy` (`none`)
- State
- Published
- Severity
- 9.2 Critical
- Published
- Feb 10, 2025
- Updated
- May 21, 2025
- Reserved
- Jan 16, 2025
Description
PAM-PKCS#11 is a Linux-PAM login module that allows a X.509 certificate based user login. Prior to version 0.6.13, if cert_policy is set to none (the default value), then pam_pkcs11 will only check if the user is capable of logging into the token. An attacker may create a different token with the user's public data (e.g. the user's certificate) and a PIN known to the attacker. If no signature with the private key is required, then the attacker may now login as user with that created token. The default to *not* check the private key's signature has been changed with commit commi6638576892b59a99389043c90a1e7dd4d783b921, so that all versions starting with pam_pkcs11-0.6.0 should be affected. As a workaround, in `pam_pkcs11.conf`, set at least `cert_policy = signature;`.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 9.2 Critical | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:L/SC:L/SI:L/SA:L | GitHub_M |
Weaknesses
- CWE-287 Improper Authentication
Affected Products
| Product | Versions |
|---|---|
pam_pkcs11OpenSC |
|
References
- https://github.com/OpenSC/pam_pkcs11/security/advisories/GHSA-8r8p-7mgp-vf56
- https://github.com/OpenSC/pam_pkcs11/commit/470263258d1ac59c5eade439c4d9caba0097e6e6
- https://github.com/OpenSC/pam_pkcs11/commit/b665b287ff955bbbd9539252ff9f9e2754c3fb48
- https://github.com/OpenSC/pam_pkcs11/commit/d9530167966a77115db6e885d459382a2e52ee9e
- https://github.com/OpenSC/pam_pkcs11/releases/tag/pam_pkcs11-0.6.13
- https://lists.debian.org/debian-lts-announce/2025/02/msg00021.html
- https://www.vicarius.io/vsociety/posts/cve-2025-24032-detect-vulnerability-in-linux-pam-module
- https://www.vicarius.io/vsociety/posts/cve-2025-24032-mitigate-linux-pam-module-vulnerability
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