Race condition in FreeBSD

1) Race condition

EUVDB-ID: #VU51949

Risk: Low

CVSSv3.1: 5.8 [CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-25584

CWE-ID: CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

Exploit availability: No

Description

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to a race condition between lookup of ".." and remounting a filesystem. A local administrator can change the root directory outside of the jail and gain full read and write access to all files and directories in the system.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

FreeBSD: 11.0 - 12.1

External links

http://www.freebsd.org/security/advisories/FreeBSD-SA-21:10.jail_mount.asc

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.