#VU18846 Resource exhaustion in FreeBSD


Published: 2019-06-19

Vulnerability identifier: #VU18846

Vulnerability risk: Medium

CVSSv3.1: 5.2 [CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2019-5599

CWE-ID: CWE-400

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
FreeBSD
Operating systems & Components / Operating system

Vendor: FreeBSD Foundation

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to an error when processing acknowledgements within the TCP loss detection algorithm  RACK ("Recent ACKnowledgment"). A remote attacker can trigger resource exhaustion by sending specially crafted TCP packets to the affected system, which causes the several linked lists, used by RACK, to grow unbounded.

Successful exploitation of the vulnerability allows an attacker to perform denial of service attack (lower network performance, consume excessive CPU), but requires that system is compiled with RACK support.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

FreeBSD: 12.0

External links
http://www.freebsd.org/security/advisories/FreeBSD-SA-19:08.rack.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.


Latest bulletins with this vulnerability


Remote DoS in FreeBSD