Summary

This is a family of stealth multipartite fast infecting viruses originating from Australia. There are at least five variants, sizes ranging from 2 to 3 kB.

Additional Details

One of the variants generates an endless loop to the partition table, making PC crash when it tries to boot from a clean floppy which has MS-DOS v4.0 - 7.0. To overcome this, use PC-DOS 7.0, MS-DOS 3.3x or a non-DOS boot floppy. Contact F-Secure anti-virus support for further instructions.

Note: Rainbow is also an alias for the WordMacro/Colors virus.

[Analysis: Mikko Hypponen, F-Secure]