During execution of an infected file the virus decrypts itself by using 5 different decryptors. However, it is not polymorphic. The virus uses several anti-debugging tricks like using INT 1,3,9 as decryptors and direct port commands.
After that it hooks INT 13h, 21h and stays memory resident. BatMan_II.3372 is a stealth virus, it changes the DOS file time stamp to 62 seconds. During execution the virus searches for *.EXE files, then writes itself to the end of them.
Based on the settings of your F-Secure security product, it will either move the file to the quarantine where it cannot spread or cause harm, or remove it.
A False Positive is when a file is incorrectly detected as harmful, usually because its code or behavior resembles known harmful programs. A False Positive will usually be fixed in a subsequent database update without any action needed on your part. If you wish, you may also:
Check for the latest database updates
First check if your F-Secure security program is using the latest updates, then try scanning the file again.
Submit a sample
After checking, if you still believe the file is incorrectly detected, you can submit a sample of it for re-analysis.
Note: If the file was moved to quarantine, you need to collect the file from quarantine before you can submit it.
Exclude a file from further scanning
If you are certain that the file is safe and want to continue using it, you can exclude it from further scanning by the F-Secure security product.
Note: You need administrative rights to change the settings.
BatMan_II sometimes corrupts files, due to a bug in it's infection routine. The corrupted files halt or reboot the system and they will not work after the disinfection either.
The virus contains a few text strings, but they are encrypted:
Bat Man II *.EXE COMMAND \NAWIAT ( --> backwards \TAIWAN )
The virus has shorter variants, too.
BatMan_II was found in the wild in USA in August 1996.