Classification

Category :

Malware

Type :

Virus

Aliases :

Cruncher

Summary

Cruncher is an unordinary virus; it stays resident in memory and infects files normally, when they are executed. In addition to this, it finally applies a self-extracting packing layer on the infected files, packing both the original code and the appended virus code.

This makes the virus more difficult to detect, especially since the packing code is stolen from the freeware DIET packer, which is similar to LZEXE and PKLITE. For this reason, several antivirus programs have had a false alarm of Cruncher in clean DIET-packed programs.

Cruncher is also the only known virus which actually saves disk space, since infected programs are usually decreased in size by 20-40%.

There are two known variants of Cruncher, V1.0 infects COM files and V2.0 infects EXE files.

Cruncher was written in 1993 by 'Masud Khafir' of the TridenT virus group.

F-Secure anti-virus products might detect Cruncher-infected files as 'possibly a DIET-packed dropper of Coffeeshop'.

Removal

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.

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 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.

Technical Details

N/A