A vulnerability was found in Yubico PAM Module up to 2.25. It has been declared as critical. This vulnerability affects the function check_user_token of the file util.c. The manipulation with an unknown input leads to a information disclosure vulnerability. The CWE definition for the vulnerability is CWE-200. The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. As an impact it is known to affect confidentiality, and availability. CVE summarizes:

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).

The bug was discovered 04/03/2018. The weakness was presented 04/04/2018 as Bug 1088027 as not defined bug report (Bugzilla). The advisory is shared for download at bugzilla.opensuse.org. This vulnerability was named CVE-2018-9275 since 04/04/2018. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1592.

The vulnerability was handled as a non-public zero-day exploit for at least 1 days. During that time the estimated underground price was around $0-$5k. The vulnerability scanner Nessus provides a plugin with the ID 120536 (Fedora 28 : pam_yubico (2018-75fdc70018)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Fedora Local Security Checks and running in the context l. The commercial vulnerability scanner Qualys is able to test this issue with plugin 277449 (Fedora Security Update for pam_yubico (FEDORA-2018-75fdc70018)).

Upgrading eliminates this vulnerability. A possible mitigation has been published 5 months after the disclosure of the vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (120536). Once again VulDB remains the best source for vulnerability data.

Productinfo

Name

• Yubico PAM Module

Version

• 2.18
• 2.19
• 2.20
• 2.21
• 2.22
• 2.23
• 2.24
• 2.25

License

• open-source

CPE 2.3info

• 🔍
• 🔍
• 🔍

CPE 2.2info

• 🔍
• 🔍
• 🔍

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

Discussion