Gattman.A is a file infecter targeted at IDC files. IDC files are proprietary script files for the popular reverse engineering tool IDA Pro. The author's purpose seems to be the creation; of a proof-of-concept file infecter with the aim of fooling security researchers. However, due to the very specific nature of the files it attempts to infect, the threat can be considered almost null.
Infected IDC files can usually be restored by opening them with a text editor and manually removing the code created by the malware.
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.
Gattman.A can arrive on the victim's computer in two ways:
Both the executable file and the IDC script needs to be executed for Gattman.A to activate. (IDC needs to be explicitly executed from inside of IDA Pro.) If the executable file is launched, it will start looking for IDC files starting from its current directory and recursing through subdirectories. When it finds a file suitable for infection, it will inject its own code into the script, maintaining the original code of the script. The injected code is responsible to recreate the executable file and execute it. This code is polymorphic: it is composed by oligomorphic IDC commands that will recreate the original binary executable, while the polymorphism consists of randomly generated comments. It is notable that the executable created by running the IDC script is constant. If the created IDC file is executed, it will recreate the binary file and will execute it. After the execution is terminated, the binary file will be removed.