Summary

On January 24th and 25th, 2004, a number of emails with a fake virus warning from Microsoft were spammed. When users view the email it attempts to download and execute a variant of VBS/Inor trojan dropper from a web site. The real address has been spoofed using a security vulnerability in Internet Explorer.

Additional Details

When an user opens the spammed email, an attept to download and execute a VBS/Inor dropper is made. If the dropper is able to execute, then a variant of W32/Dumaru worm is installed into system. Inor drops the worm to "C:\2.exe".

We have received reports that different variants of W32/Dumaru have been dropped from the web site. Further information about W32/Dumaru is available within the following descriptions:
http://www.f-secure.com/v-descs/dumaru_y.shtml
http://www.f-secure.com/v-descs/dumaru_z.shtml

At the time of writing this description, the trojan downloader is removed from the web site.

Below is a screenshot of the message:



Detection

Detection in F-Secure Anti-Virus was published on January 26th, 2004 at early morning in update:

[FSAV_Database_Version]
Version=2004-01-26_01

Technical Details: Katrin Tocheva and Sami Rautiainen, January 26th, 2004;

F-Secure Corporation