Vulnerability identifier: #VU35855

Vulnerability risk: Medium

CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2019-12209

CWE-ID: CWE-200

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
pam-u2f
Web applications / Other software

Vendor: Yubico

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.

Mitigation
Install update from vendor's website.

Vulnerable software versions

pam-u2f: 1.0.7

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External links
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
http://developers.yubico.com/pam-u2f/Release_Notes.html
http://github.com/Yubico/pam-u2f/commit/7db3386fcdb454e33a3ea30dcfb8e8960d4c3aa3
http://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/5FOR4ADC356JPCHAJI5UXZORLC3VNBPS/
http://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/ZCGU6UQLI3ZTW3UYCTMQW7VDL5M4LCWR/

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.