Users of older versions of Symantec's anti-virus software have been warned of an exploit that might mean users looking for virus updates get redirected to hacker sites instead.
The issue concerns Symantec LiveUpdate, a component of Norton Anti-Virus which checks for fresh virus signature definitions and installs them from Symantec's Web site.
A group of German hackers, called Phenoelit, have published an advisory which explains how Version 1.4 of LiveUpdate (which ships with Norton Antivirus 5.x) might be turned into a distribution medium for hostile code. The same trick might be used to penetrate systems, they warn.
Version 1.6 of LiveUpdate (which ships with Norton Antivirus 2001 and 2002) is immune to the particular attack, but it can be prevented from downloading virus definitions or product updates using the exploit. Phenoelit believes there's a denial of service risk even for the newer product. If the attacker were to point people to a very large download file, a scheduled LiveUpdate session in a medium sized company might lead to network degradation and outages due to the large amount of traffic generated.
Eric Chien, chief researcher at Symantec's antivirus research lab, said that the DNS attacks Phenoelit details in its advisory are standard Internet attacks that involve DNS spoofing, poisoning and redirection. Symantec rates the problem, which it said is not particular to them, as a medium class risk.
Only a small percentage of Symantec's users would be using Version 1.4 of LiveUpdate (which has been superseded for well over a year), Chien told us. Those who are should consider updating to Version 1.6 of LiveUpdate, which contains cryptographically signed signature updates that can't be easily forged.
More information on the issue and Symantec's advice to its customers can be found here. ®