Remote DoS in FreeBSD ipfilter

1) Memory leak

EUVDB-ID: #VU6393

Risk: High

CVSSv3.1: 7.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2017-1081

CWE-ID: CWE-401 - Missing release of memory after effective lifetime

Exploit availability: No

Description

The vulnerability allows a remote attacker to cause denial of service conditions.

The vulnerability exists due to an error within ipfilter(4) implementation, when processing specially crafted fragmented packets and the packet filter is configured to perform stateful packet inspection, using the "keep state" or "keep frags" rule options. A remote attacker can send a series of specially crafted fragmented packets to vulnerable system and trigger kernel panic and system reboot.

Successful exploitation of the vulnerability may allow an attacker to perform a denial of service (DoS) attack.

Mitigation

Install patch from vendor's website:
https://security.FreeBSD.org/patches/SA-17:04/ipfilter.patch
https://security.FreeBSD.org/patches/SA-17:04/ipfilter.patch.asc

Vulnerable software versions

FreeBSD: 10.0 - 11.0

External links

http://www.freebsd.org/security/advisories/FreeBSD-SA-17:04.ipfilter.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.