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.
Disinfection & Removal
Description Created: Mikko Hypponen, F-Secure