This type of virus infects COM files. A COM file is a small (less than 65 kilobytes) binary executable file. That format was widely used during DOS operating system era. However this format was used for some utilities in Windows 95, 98 and ME. In Windows NT, 2000 and XP there also exist COM files, but they are mostly files in EXE format and were given COM extension for backward compatibility reasons.
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.
A COM infector can be prepending (writes itself before the original file), appending (writes itself to the end of the original file), overwriting (overwrites the original file with its own code), inserting (inserts itself into gaps inside the original file) and companion (renames the original file and writes itself with the original file's name). A COM infector can be memory resident and non-memory resident. Memory resident viruses stay active in memory, trap one or more system functions (usually interrupt 21h) and infect files while they are accessed. Non-memory resident viruses search for COM files on a hard disk and infect them.
A COM infector can be non-encrypted, encrypted or polymorphic. An encrypted or polymorphic virus consists of one or more decryptors and a main code. A decryptor decrypts main virus code before it could be started. Encrypted viruses usually use fixed or variable key decryptors while polymorphic viruses have decryptors that are randomly generated from processor instructions and contain a lot of commands that are not used in decryption process.