Worm:W32/Downaduprun.A

Classification

Malware

Worm

W32

Worm:W32/downaduprun, downaduprun, Worm:W32/Downaduprun.A

Summary

Worm:W32/Downaduprun.A is generic detection of the malicious autorun files created by Worm:W32/Downadup, which exploit the Windows Autorun functionality to spread the worm.

Security programs use generic detections that look for broad patterns of code or behavior to identify similar programs or files. If you suspect the file was incorrectly detected, go to: Removal: Resolving a False Positive.

Removal

Automatic action

Based on the settings of your F-Secure security product, it will either move the file to the quarantine where it cannot spread or cause harm, or remove it.

Resolving a False Positive

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:

  • Check for the latest database updates

    First check if your F-Secure security program is using the latest detection database updates, then try scanning the file again.

  • Submit a sample

    After checking, if you still believe the file is incorrectly detected, you can submit a sample of it to F-Secure Labs for re-analysis.

    NOTE If the file was moved to quarantine, you need to collect the file from quarantine before you can submit it.

  • 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.

Find out more

Knowledge Base

Find the latest advice in our Community Knowledge Base.

User Guide

See the user guide for your product on the Help Center.

Contact Support

Chat with or call an expert for help.

Submit a sample

Submit a file or URL for further analysis.

Technical Details

Typical Autorun.inf files are very small in size. The Downadup worm inflates the size of its autorun.inf in an attempt to avoid detection by antivirus signature scanners. Binary characters are used to inflate the file size. These binary characters are ignored by the Windows operating system.

Execution

On execution of the file, Windows runs the bloated file and finds the following command buried in the garbage text:

  • Open=RUNDLL32.EXE .\RECYCLER\jwgvsq.vmx

This command executes a DLL called jwgvsq.vmx from a hidden folder on the removable drive containing the malicious autorun.inf.

Note

This malware is discussed in the following Labs Weblog post:

Date Created: 2009-01-20 10:51:34.0

Date Last Modified: 2010-09-29 09:53:51.0