W32.Kittykat is a virus that splits itself into many parts, and adds these parts to all RAR archive files in the current directory and the parent directory.
The virus may arrive as an archive file. The virus requires that the archive is extracted with the full directory structure, and that the file start.bat is then executed.
When W32.Kittykat is executed, it performs the following actions:
1. Reconstructs itself as the following file: [RANDOM FILENAME].exe
2. Displays a message to announce its presence.
3. Searches for files to infect. The virus has no infection marker, so an already infected RAR archive file in the current or parent directory will be infected repeatedly.
Users should be cautious with any unusual RAR files they encounter in email or otherwise. Thankfully, this new threat isn't prevelant in-the-wild.
Kittykat - New RAR virus threat