One unusual "feature" of this virus is that it will search the disk for the string "Microsoft" and change it into "MACROSOFT". The virus will not infect programs if the environment contains SYSLOCK=@.
Once detected, the F-Secure security product will automatically disinfect the suspect file by either deleting it or renaming it.
Two minor variants, which will transform the string "Microsoft" into "MACHOSOFT". One is very close to the original SysLock virus, with only one byte different, but the other has been modified somewhat.
Activates in December and plays "Oh, Tannenbaum".
The last variant is 2232 bytes long and known as "Cookie", because it may display the message
I want a COOKIE!