Type File virus
Date Discovered 1991.11
Place of Origin Germany
Source Language
Platform DOS
File Type(s) .com
Infection Length 1,090 or 1,134 bytes
Reported Costs

Karin also known as RedStar is a direct action infector from 1991. It displays a birthday message to someone named Karin.


When a file infected with Karin is executed, it searches the current directory for uninfected .com programs. There will be no change in the file's date or time. When it finds one, it prepends its either 1,090 or 1,134 bytes of code to the file. It makes no attempt to avoid COMMAND.COM.

On the 23rd of October, it repeatedly displays the message "Karin hat GEBURTSTAG", German for "It's Karin's Birthday". The virus will do this in an infinite loop, so the computer will have to be rebooted. This will not be possible if COMMAND.COM is infected, so a clean disk will be needed.

Name and Origin

The message that is displayed by the virus suggests that it is from Germany or a German speaking nation. It gets its name from the displayed text. It also contains text that is not displayed, including "REDSTAR" from which it gets one of its aliases.


Patricia Hoffman. Online VSUM, Karin Virus.

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