W32/Nuwar aka the Storm worm ever since it debut in Nov 2006 has relentlessly flooded internet users with its ever-changing email campaigns. With the storm worm authors having this uncanny knack of using sensationalist themes that draw public attention, the morbid curiosity it has generated has ensured that is the most blogged about piece of malware this year!

The latest campaign is an HTML formatted email using the Labor Day theme, inviting users to view an online greeting card. A copy of the spammed email is as follows:

The authors have used anchor tags in HTML to mask the greeting card link so that an unsuspecting user does not notice that it actually points to a malicious ip address. Hovering the mouse over this disguised link is a quick and dirty way to reveal the real destination address. Users who fall for this bait are directed to the following Happy Labor Day page.

Everything looks hunky-dory except an unsuspecting user is served an xor’ed exploit cocktail in the background. In addition to the usual Microsoft exploits, QuickTime and WinZip buffer overflow exploits are also attempted on a user’s machine. Given the slim likelihood of vulnerable third party applications being up to date on a user’s machine, it increases the attacker’s chances of a successful exploitation. Especially since most applications do not support automated updates and it is left up to the users to first find out if they have a vulnerable version of the application and then manually patch it.

Enterprise customers have the bandwidth and resources to ensure every machine on the corporate network is fully patched. It is usually home consumers - the low hanging fruit that fall prey to these malicious tactics. For users wanting to check if third party applications on their systems are vulnerable, a free online resource to visit would be the Secunia Software Inspector. Happy Patching