Privilege escalation via USB drivers in FreeBSD

1) Out-of-bounds write

EUVDB-ID: #VU34101

Risk: Low

CVSSv4.0: 4 [CVSS:4.0/AV:P/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2020-7459

CWE-ID: CWE-787 - Out-of-bounds write

Exploit availability: No

Description

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

The vulnerability exists due to missing length validation code common to multiple USB network drivers. A local user can use a malicious USB device to write beyond the end of an allocated network packet buffer, trigger buffer overflow and execute arbitrary code on the system with elevated privileges.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

FreeBSD: 11.0 - 12.1

CPE2.3

• cpe:2.3:o:freebsd_foundation:freebsd:11.0:*:*:*:*:*:*:*
• cpe:2.3:o:freebsd_foundation:freebsd:11.1:*:*:*:*:*:*:*
• cpe:2.3:o:freebsd_foundation:freebsd:11.2:*:*:*:*:*:*:*

External links

http://security.FreeBSD.org/advisories/FreeBSD-SA-20:21.usb_net.asc

Q & A

Can this vulnerability be exploited remotely?

No. The attacker should have physical access to the system in order to successfully exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

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