Kelvir, IM-Worm.Kelvir.A


Kelvir is an IM (Instant Messenger) worm that spreads by sending a link to its file using MSN Messenger. The worm also tries to download and run a file from Internet.

Automatic action

To get rid of this worm it is enough to delete its file from a hard disk. The latest versions of F-Secure Anti-Virus can automatically disable (rename) the worm's infected file. If automatic disinfection fails, please select 'Delete' disinfection action for the worm's file when it is detected. Instructions are here:

Please restart a computer after disinfection.

Suspect a file is incorrectly detected (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 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.

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Submit a sample

Submit a file or URL for further analysis.

Technical Details




The worm's file is a PE executable about 49 kilobytes long. The file is packed with a file compressor. The worm is written in Visual Basic.

The worm's file usually arrives on a computer with the MSN instant message message that looks like that:

lol! see it! u'll like it

The message contains a link that points to the worm's file named 'omg.pif' located on the '' webserver. When this file is downloaded and run by a user, it infects a computer and continues its spreading cycle by sending instant messages to all found MSN Messenger contacts.

Additionally the worm tries to download the following file:

This file is saved to the root of C:\ drive as 'dumprep.exe' and is then executed. The downloaded file is a variant of RBot backdoor and it is detected as ''. At the moment of the creation of this description the 'me.jpg' file was not accessible any longer.