Use-after-free in FreeBSD

1) Use-after-free

EUVDB-ID: #VU35661

Risk: Low

CVSSv3.1: 6.8 [CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2019-5606

CWE-ID: CWE-416 - Use After Free

Exploit availability: No

Description

The vulnerability allows a local authenticated user to execute arbitrary code.

In FreeBSD 12.0-STABLE before r349805, 12.0-RELEASE before 12.0-RELEASE-p8, 11.3-STABLE before r349806, 11.3-RELEASE before 11.3-RELEASE-p1, and 11.2-RELEASE before 11.2-RELEASE-p12, code which handles close of a descriptor created by posix_openpt fails to undo a signal configuration. This causes an incorrect signal to be raised leading to a write after free of kernel memory allowing a malicious user to gain root privileges or escape a jail.

Mitigation

Install update from vendor's website.

Vulnerable software versions

FreeBSD: 11.0 - 12.0

External links

http://packetstormsecurity.com/files/153748/FreeBSD-Security-Advisory-FreeBSD-SA-19-13.pts.html
http://security.FreeBSD.org/advisories/FreeBSD-SA-19:13.pts.asc
http://security.netapp.com/advisory/ntap-20190814-0003/

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.