CVE-2018-9275 — In check_user_token in util

In check_user_token in util.c in the Yubico PAM module (aka pam_yubico) 2.18 through 2.25, successful logins can leak file descriptors to the auth mapping file, which can lead to information disclosure (serial number of a device) and/or DoS (reaching the maximum number of file de

01What is this vulnerability?

In check_user_token in util.c in the Yubico PAM module (aka pam_yubico) 2.18 through 2.25, successful logins can leak file descriptors to the auth mapping file, which can lead to information disclosure (serial number of a device) and/or DoS (reaching the maximum number of file descriptors).

02Affected products

Vendor	Product	Versions
n	a / n/a	n/a

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2018-04-04T18:00:00.000Z
• Last modified: 2024-09-17T04:23:59.373Z

09References

• bugzilla.opensuse.org — https://bugzilla.opensuse.org/show_bug.cgi?id=1088027
• github.com — https://github.com/Yubico/yubico-pam/commit/0f6ceabab0a8849b47f67d727aa526c26560…
• github.com — https://github.com/Yubico/yubico-pam/issues/136