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

high Nessus Plugin ID 100497

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Synopsis

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

Description

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.

Solution

Update the affected packages.

Plugin Details

Severity: High

ID: 100497

File Name: freebsd_pkg_51d1282d420e11e782c514dae9d210b8.nasl

Version: 3.9

Type: local

Family: FreeBSD Local Security Checks

Published: 5/30/2017

Updated: 12/17/2025

Configuration: Enable paranoid mode

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Low

Score: 3.6

CVSS v2

Risk Factor: High

Base Score: 7.8

Temporal Score: 5.8

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:C

CVSS Score Source: CVE-2017-1081

CVSS v3

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: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

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

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

Exploit Ease: No known exploits are available

Patch Publication Date: 5/26/2017

Vulnerability Publication Date: 4/27/2017

Reference Information

CVE: CVE-2017-1081

FreeBSD: SA-17:04.ipfilter

Detections

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