Exposure of TACACS+ shared secret in pam_tacplus

1) Inclusion of Sensitive Information in Log Files

EUVDB-ID: #VU109287

Risk: Medium

CVSSv4.0: 2.1 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:H/SI:L/SA:N/E:U/U:Green]

CVE-ID: CVE-2020-13881

CWE-ID: CWE-532 - Information Exposure Through Log Files

Exploit availability: No

Description

The vulnerability allows a local user to gain access to sensitive information.

The vulnerability exists due to software stores TACACS+ encryption key into log file if the DEBUG loglevel and journald are used. A local user can read the log files and gain access to sensitive data. This information can be used to decrypt communication between the TACACS+ server and the end user, exposing authentication credentials.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

pam_tacplus: 1.3.8 - 1.5.1

CPE2.3

• cpe:2.3:a:kravietz:pam_tacplus:1.3.8:*:*:*:*:*:*:*
• cpe:2.3:a:kravietz:pam_tacplus:1.3.9:*:*:*:*:*:*:*
• cpe:2.3:a:kravietz:pam_tacplus:1.4.1:*:*:*:*:*:*:*

External links

https://github.com/kravietz/pam_tacplus/issues/149
https://github.com/kravietz/pam_tacplus/commit/4a9852c31c2fd0c0e72fbb689a586aabcfb11cb0
https://www.openwall.com/lists/oss-security/2020/06/08/1
https://lists.debian.org/debian-lts-announce/2020/06/msg00007.html
https://www.arista.com/en/support/advisories-notices/security-advisories/11705-security-advisory-50
https://usn.ubuntu.com/4521-1/
https://lists.debian.org/debian-lts-announce/2021/08/msg00006.html

Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

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