Link following in chrony

1) Link following

EUVDB-ID: #VU46134

Risk: Medium

CVSSv4.0: 1.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2020-14367

CWE-ID: CWE-59 - Improper Link Resolution Before File Access ('Link Following')

Exploit availability: No

Description

The vulnerability allows a remote attacker to compromise the target system.

The vulnerability exists due to a symlink following issue when creating the PID file under the "/var/run/chrony" folder. A remote authenticated attacker can create a symlink with the default PID file name pointing to any destination file in the system, resulting in data loss and a denial of service (DoS).

Mitigation

Install updates from vendor's website.

Vulnerable software versions

chrony: 1.0 - 3.5

CPE2.3

• cpe:2.3:a:mlichvar:chrony:1.0:*:*:*:*:*:*:*
• cpe:2.3:a:mlichvar:chrony:1.1:*:*:*:*:*:*:*
• cpe:2.3:a:mlichvar:chrony:1.18:*:*:*:*:*:*:*

External links

https://bugzilla.redhat.com/show_bug.cgi?id=1870298
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/6WKABKNLCSC3MACCWU6OM2YGWVWFWFMU/
https://security.gentoo.org/glsa/202008-23

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

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