Security threats Toolkit

Linux kernel flaw allows DoS attack

Published: 25 Oct 2004 17:40 BST

Linux distributor Novell SuSE released a security advisory with a severity rating of nine out of 10 last week warning of a flaw in Linux kernel 2.6..

The bug affects the company's enterprise and consumer products-- SuSE Linux Enterprise Server 9 and SuSE Linux Professional 9.1.

Roman Drahtmueller, head of Linux security at SuSE Linux, said this version of the kernel is available to all Linux distributers, but as SuSE is one of the few commercial distributions to actually use the 2.6 kernel it was a priority for them to resolve the security hole quickly.

Red Hat's enterprise product, Red Hat Enterprise Linux, is not affected by the flaw as it uses version 2.4 of the kernel, according to Mark Cox, who works for the Red Hat security response team.

The flaw will allow a malicious remote user to crash a PC that is running one of the affected SuSE products and a firewall, by sending a specially crafted IP packet.

SuSE has advised users to disable firewall logging of IP and TCP options and to update the kernel. Version 2.6.8 of the kernel contains a fix for this bug, as does the latest version, 2.6.9, which was released last week.

The full SuSE Linux advisory can be found here. An updated version of the Linux kernel can be downloaded from the kernel Web site.

It's a busy time for the Linux distributors, with Red Hat warning users about a phishing email which is disguised as an official security update.