Viral Rewind: Virus.DOS.Leprosy.Skism

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. Skism is a variant of the Leprosy family of viruses wirtten for DOS. Here the virus infects any .COM or .EXE files at random upon execution. It is not memory-resident so infection only spreads upon each execution of an infected program. The thing about Skism (and most other variants of Leprosy) is how they infect programs and spread their viral code. Skism essentially makes the original executable program inoperative (it runs but doesn't do what it normally should) and instead simply runs it's viral infection routine infecting other executables. This will be easy to notice as programs aren't working like they should be. Downside is because of how it infects, the files are non-recoverable and must be replaced with clean copies from backups.

The payload:
Whenever the date falls on the 25th of the month and it is a Friday (so it must be Friday the 25th, nothing else) Skism displays a grahpical payload showing a person with "Skism" and it displays the following:
"The man who brought you 622, Skism One, Captain Trips, and Sub-Zero now shanks you again, with his latest..."

"Skism 1992 - Virus!!!!
Get a late pass!"

At this point the system will hang requiring a reboot. However, because Skism infects .COM files it will infect COMMAND.COM causing Skism to launch its payload everytime the system is started on the payload date.

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