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Worm:W32/Downaduprun.A

Classification

Category: Malware

Type: Worm

Aliases: 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.

Generic detections are broad patterns of code or behavior that are used by security software to identify programs or files. If you suspect the detected file was incorrectly identified, go to: Removal: Resolve a False Positive.

Removal


Automatic action

Based on the settings of your F-Secure security product, it will either automatically delete, quarantine or rename the detected program or file, or ask you for a desired action.

Resolve a False Positive

Security programs will sometimes unintentionally identify a clean program or file as malicious if its code or behavior is similar to a known harmful program or file. This is known as a False Positive. In most cases, a False Positive is fixed in a subsequent database release. If you suspect the detected file is a False Positive, you can:

Knowledge Base

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About the product

See the manual for your F-Secure product on the Help Center.

Contact Support

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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