Asherons Call: You Could Already Be Infected

Threat Advisory: Network Associates McAfee AVERT Raises Risk Assessment to Medium on Newly Discovered W32/Sasser.worm

BEAVERTON, Oregon, May 1 /PRNewswire-FirstCall/ -- Network Associates, Inc. (NYSE: NET - News) the leading provider of intrusion prevention solutions, today announced that McAfee® AVERT(TM) (Anti-virus and Vulnerability Emergency Response Team), the world-class research division of Network Associates, has discovered the first self-executing worm to attack the MS04-011 vulnerability announced by Microsoft in April. McAfee AVERT has raised the risk assessment to medium for W32/Sasser.worm, also known as Sasser, due to it's prevalence in the field and it's ability to move without the support of email, which has been the primary vehicle of delivery for most of the worms seen recently. This new worm is a self-executable program that spreads by scanning random IP addresses for exploitable systems. To date, McAfee AVERT has received several reports of the worm being stopped or infecting users on several continents, with most of the reports coming from Europe.

Symptoms

Sasser is a self-executing worm that spreads by exploiting the Microsoft MS04-011 vulnerability http://www.microsoft.com/technet/security/bulletin/MS04-011.mspx. The primary purpose of the worm seems to be to spread to as many vulnerable machines as possible by exploiting un-patched Windows systems, giving it the ability to execute without requiring any action on the part of the user. Once activated the worm copies itself to a folder in the Windows System directory and adds a registry run key to load at system start-up.

Pathology

After being executed, Sasser scans random IP addresses for exploitable systems. When one is found, the worm exploits the vulnerable system by creating a script and executing it. This script instructs the target victim to download and execute the worm from the infected host. The infected host accepts this FTP traffic on TCP port 5554.

Cure

Immediate information and cure for this worm can be found online at the Network Associates McAfee AVERT site located at http://vil.nai.com/vil/content/v_125007.htm. McAfee AVERT is advising its customers to update to the 4355 DATs to stay protected.

McAfee AVERT Labs is one of the top-ranked anti-virus and vulnerability research organizations in the world, employing researchers in offices on five continents. McAfee AVERT protects customers by developing and providing solutions that are created through the combined efforts of McAfee AVERT researchers and McAfee AVERT AutoImmune technology, which applies advanced heuristics, generic detection and ActiveDAT technology to generate cures for previously undiscovered viruses.

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