Dagger is a simple direct action infector of COM files. It's 483 bytes
in size and is not encrypted.
Dagger activates on tuesdays, when an infected file is executed and the
minutes of the hour are less than 40. At this time it tries to display
text "DaGGER 2", overwrite the 100 first sectors of drive C: and empty
CMOS. Due to programming errors, both the text display and the
overwriting will fail, but the virus will succesfully overwrite the
contents of the CMOS memory.
[Analysis: Mikko Hypponen, F-Secure]