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/
Removal
Based on the settings of your F-Secure security program, it will either automatically delete, quarantine or rename the detected program or file, or ask you for a desired action.
A False Positive is when a file is incorrectly detected as harmful, usually because its code or behavior resembles known harmful programs. A False Positive will usually be fixed in a subsequent database update without any action needed on your part. If you wish, you may also:
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Check for the latest database updates
First check if your F-Secure security program is using the latest updates, then try scanning the file again.
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Submit a sample
After checking, if you still believe the file is incorrectly detected, you can submit a sample of it for re-analysis.
Note: If the file was moved to quarantine, you need to collect the file from quarantine before you can submit it.
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Exclude a file from further scanning
If you are certain that the file is safe and want to continue using it, you can exclude it from further scanning by the F-Secure security product.
Note: You need administrative rights to change the settings.
Technical Details
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
In addition, this variant starts 32-182 parallel threads to download the main page in an infinite loop, instead of the 16-96 of the previous variant.
The attack will trigger after 12th of February.
For more information on Doomjuice.A see: