[Fwd: [SA11980] Linux Kernel Netfilter TCP Option Matching Denial of Service Vulnerability]

[Fwd: [SA11980] Linux Kernel Netfilter TCP Option Matching Denial of Service Vulnerability]

[Juan Hernandez]

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I thought you guys would be interested in this since I haven't read 
anything today in this mailing list

Juan

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From: Secunia Security Advisories <sec-adv@secunia.com>
To: hvjuan@kanux.com
Subject: [SA11980] Linux Kernel Netfilter TCP Option Matching Denial of Service Vulnerability
Date: Thu, 1 Jul 2004 15:17:27 +0200
Message-ID: <200407011317.i61DHRf1020304@secunia.com>


TITLE:
Linux Kernel Netfilter TCP Option Matching Denial of Service
Vulnerability

SECUNIA ADVISORY ID:
SA11980

VERIFY ADVISORY:
http://secunia.com/advisories/11980/

CRITICAL:
Moderately critical

IMPACT:
DoS

WHERE:
From remote

OPERATING SYSTEM:
Linux Kernel 2.6.x
http://secunia.com/product/2719/

DESCRIPTION:
Adam Osuchowski and Tomasz Dubinski have reported a vulnerability in
the Linux kernel, which can be exploited by malicious people to cause
a DoS (Denial of Service).

The vulnerability is caused due to the use of an incorrect variable
type within the "tcp_find_option()" function of the netfilter
subsystem. This can be exploited by sending a specially crafted TCP
packet, which causes the kernel to enter an infinite loop and consume
all available CPU resources.

Successful exploitation requires that iptables is used with rules
matching TCP options ("--tcp-option").

SOLUTION:
Don't use any rules matching TCP options.

PROVIDED AND/OR DISCOVERED BY:
Adam Osuchowski and Tomasz Dubinski

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