F-Secure Virus Descriptions : Oropax

When this virus activates it will just repeatedly play three melodies. Infected files grow by a variable number of bytes, so their length becomes a multiple of 51 bytes in length. This virus stays resident in memory, but it will not infect other programs when they are executed. Instead it will search for a file to infect when files are created or deleted, a subdirectory is created or the access mode of a file is changed. A few other functions may also trigger an infection.

The virus uses a random number generator to decide when to become active, and if it does, it will start playing 5 minutes after an infected program is run.