FreeBSD : FreeBSD -- Resource exhaustion in non-default RACK TCP stack (c294c2e6-b309-11e9-a87f-a4badb2f4699) (ERC)

high Nessus Plugin ID 127551



The remote FreeBSD host is missing a security-related update.


While processing acknowledgements, the RACK code uses several linked lists to maintain state entries. A malicious attacker can cause the lists to grow unbounded. This can cause an expensive list traversal on every packet being processed, leading to resource exhaustion and a denial of service. Impact : An attacker with the ability to send specially crafted TCP traffic to a victim system can degrade network performance and/or consume excessive CPU by exploiting the inefficiency of traversing the potentially very large RACK linked lists with relatively small bandwidth cost.


Update the affected package.

See Also

Plugin Details

Severity: High

ID: 127551

File Name: freebsd_pkg_c294c2e6b30911e9a87fa4badb2f4699.nasl

Version: 1.2

Type: local

Published: 8/12/2019

Updated: 1/6/2020

Configuration: Enable paranoid mode

Risk Information


Risk Factor: Low

Score: 3.6


Risk Factor: High

Base Score: 7.8

Temporal Score: 5.8

Vector: AV:N/AC:L/Au:N/C:N/I:N/A:C

Temporal Vector: E:U/RL:OF/RC:C


Risk Factor: High

Base Score: 7.5

Temporal Score: 6.5

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Temporal Vector: E:U/RL:O/RC:C

Vulnerability Information

CPE: p-cpe:/a:freebsd:freebsd:FreeBSD, cpe:/o:freebsd:freebsd

Required KB Items: Host/local_checks_enabled, Host/FreeBSD/release, Host/FreeBSD/pkg_info, Settings/ParanoidReport

Exploit Ease: No known exploits are available

Patch Publication Date: 7/30/2019

Vulnerability Publication Date: 6/19/2019

Reference Information

CVE: CVE-2019-5599

FreeBSD: SA-19:08.rack