FreeBSD : FreeBSD -- ipfilter(4) fragment handling panic (51d1282d-420e-11e7-82c5-14dae9d210b8)

High Nessus Plugin ID 100497


The remote FreeBSD host is missing one or more security-related updates.


ipfilter(4), capable of stateful packet inspection, using the 'keep state' or 'keep frags' rule options, will not only maintain the state of connections, such as TCP streams or UDP communication, it also maintains the state of fragmented packets. When a packet fragments are received they are cached in a hash table (and linked list). When a fragment is received it is compared with fragments already cached in the hash table for a match. If it does not match the new entry is used to create a new entry in the hash table. If on the other hand it does match, unfortunately the wrong entry is freed, the entry in the hash table. This results in use after free panic (and for a brief moment prior to the panic a memory leak due to the wrong entry being freed).
Impact : Carefully feeding fragments that are allowed to pass by an ipfilter(4) firewall can be used to cause a panic followed by reboot loop denial of service attack.


Update the affected packages.

See Also

Plugin Details

Severity: High

ID: 100497

File Name: freebsd_pkg_51d1282d420e11e782c514dae9d210b8.nasl

Version: $Revision: 3.3 $

Type: local

Published: 2017/05/30

Modified: 2017/07/20

Dependencies: 12634

Risk Information

Risk Factor: High

Vulnerability Information

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

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

Patch Publication Date: 2017/05/26

Vulnerability Publication Date: 2017/04/27

Reference Information

CVE: CVE-2017-1081

FreeBSD: SA-17:04.ipfilter