Multiple BSD ipfw / ip6fw ECE Bit Filtering Evasion

High Nessus Plugin ID 12118


Firewalling rules may be circumvented.


The remote host seems vulnerable to a bug wherein a remote attacker can circumvent the firewall by setting the ECE bit within the TCP flags field. At least one firewall (ipfw) is known to exhibit this sort of behavior.

Known vulnerable systems include all FreeBSD 3.x ,4.x, 3.5-STABLE, and 4.2-STABLE.


If you are running FreeBSD 3.X, 4.x, 3.5-STABLE, 4.2-STABLE, upgrade your firewall. If you are not running FreeBSD, contact your firewall vendor for a patch.

Plugin Details

Severity: High

ID: 12118

File Name: ece_flag.nasl

Version: $Revision: 1.19 $

Type: remote

Family: Firewalls

Published: 2004/03/30

Modified: 2014/05/25

Risk Information

Risk Factor: High


Base Score: 7.5

Temporal Score: 6.2

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

Temporal Vector: CVSS2#E:F/RL:OF/RC:C

Vulnerability Information

Required KB Items: Settings/ParanoidReport

Exploit Available: true

Exploit Ease: Exploits are available

Vulnerability Publication Date: 2001/01/23

Reference Information

CVE: CVE-2001-0183

BID: 2293

OSVDB: 1743