TCP spoofing in FreeBSD pf

1) Input validation error

EUVDB-ID: #VU83985

Risk: Medium

CVSSv4.0: 2.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2023-6534

CWE-ID: CWE-20 - Improper input validation

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform spoofing attack.

The vulnerability exists due to missing validation of TCP sequence numbers on inbound packets in pf(4). A remote attacker can guess the connection's port numbers and inject packets into existing TCP streams, resulting in spoofing attack.

This could be used to implement a denial-of-service attack for hosts behind the firewall, for example by sending TCP RST packets to the host.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

FreeBSD: 12.0 - 14.0

CPE2.3

• cpe:2.3:o:freebsd_foundation:freebsd:12.0:*:*:*:*:*:*:*
• cpe:2.3:o:freebsd_foundation:freebsd:12.1:*:*:*:*:*:*:*
• cpe:2.3:o:freebsd_foundation:freebsd:12.2-RELEASE-p6:*:*:*:*:*:*:*

External links

https://www.freebsd.org/security/advisories/FreeBSD-SA-23:17.pf.asc

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

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