Information disclosure in pam-u2f - CVE-2019-12209
Published: June 4, 2019 / Updated: August 8, 2020
Vulnerability identifier: #VU35855
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2019-12209
CWE-ID: CWE-200
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Yubico
Affected software:
pam-u2f
pam-u2f
Detailed vulnerability description
The vulnerability allows a remote non-authenticated attacker to gain access to sensitive information.
Yubico pam-u2f 1.0.7 attempts parsing of the configured authfile (default $HOME/.config/Yubico/u2f_keys) as root (unless openasuser was enabled), and does not properly verify that the path lacks symlinks pointing to other files on the system owned by root. If the debug option is enabled in the PAM configuration, part of the file contents of a symlink target will be logged, possibly revealing sensitive information.
How to mitigate CVE-2019-12209
Install update from vendor's website.
Sources
- http://lists.opensuse.org/opensuse-security-announce/2019-07/msg00012.html
- http://lists.opensuse.org/opensuse-security-announce/2019-07/msg00018.html
- http://www.openwall.com/lists/oss-security/2019/06/05/1
- https://developers.yubico.com/pam-u2f/Release_Notes.html
- https://github.com/Yubico/pam-u2f/commit/7db3386fcdb454e33a3ea30dcfb8e8960d4c3aa3
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/5FOR4ADC356JPCHAJI5UXZORLC3VNBPS/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/ZCGU6UQLI3ZTW3UYCTMQW7VDL5M4LCWR/