When a file infected by a Geek virus is run for the first time, the virus copies itself to the interrupt table at memory location 0000:0200h. The next unused location is 0000:03D4h. If the byte at 0000:03C1 is 'x', the virus considers itself already resident. This comes from the text 'dex' at the end of the virus file.
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.
Other strings in the virus are 'GEEK' and '0v7a', the first might be a name, the second looks like a version number. The final 'x' is the only part of this that is used. Dos calls are used to get/set the INT 21h interrupt vector. Infected EXE files have their initial stack pointer set to A000h. This is used to determine whether to exit as a COM file or EXE file.
The INT 21h handler intercepts calls to DOS function 4Bh (load program). File attribute, date and time are preserved. The infection signature is different for com and exe files. For infected COM files, the first byte of the file is 0Eh (push cs). For EXE's the offset to first relocatable item (low byte) is DEh.
Any file beginning with 'M' is treated as an EXE file. EXE files are filled to the next paragraph boundary before the virus is appended, COM files are simply appended to.
On the 29th day of any month, a random sector is overwritten by the virus code/data instead of infecting a file.