F-Secure Virus Descriptions : Doomjuice.B

Summary

A new variant of Doomjuice worm was found on 11th of February. This one also attacks against www.microsoft.com.

F-Secure monitors the ongoing Mydoom-related attacks in our Weblog: http://www.f-secure.com/weblog/

Detailed Description

Doomjuice.B is similar to to the original Doomjuice.A. This variant tries to improve the Distributed Denial-of-Service attack on www.microsoft.com. The size of this variant is smaller, as Doomjuice.B does not contain or drop the source code of Mydoom.A.

System Infection

After entering the system Doomjuice copies itself to the Windows System Directory as 'regedit.exe'. The copy is added to the registry as

HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\NeroCheck HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\NeroCheck

Distributed Denial-of-Service Attack

Doomjuice.B attacks www.microsoft.com via HTTP protocol like Doomjuice.A, but it tries to improve the Distributed Denial-of-Service attack. It sets random HTTP headers to make it more difficult to filter out the attack traffic:

 User-Agent: Mozilla/4.0
 User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1)
 User-Agent: Mozilla/4.0 (compatible; MSIE 5.0; Windows NT 5.0)
 Accept-Encoding: gzip, deflate
 Accept-Language: en
 Accept-Language: en-us