Trojan-Spy:W32/Nuklus.A is a modular malware application mainly used for stealing online bank credentials.
It is installed to the system using a browser exploit. According to published reports, the links to sites containing the exploits were spammed.
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 detection database 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.
The trojan's main file, iexplore.exe, is downloaded via a browser exploit. When run, iexplore.exe drops the following files:
It creates the following service:
It creates the following registry value:
The trojan injects itself to the web browser and runs the rest of the code in the context of the browser process.
After the installation, it contacts the server in the control file and starts to wait for commands. The remote server may instruct the trojan to execute any of the following actions:
The remote server may instruct the trojan to download additional components using a plugin system. The plugin system consists of DLL files that are loaded by the main trojan or installed to the system using other methods, like browser helper objects (BHO) for Internet Explorer (IE). Plugins communicate with the control server using HTTP requests.
The following DLL files are basic plugins that may be installed to system:
Other plugins can also be installed to infected system.
The remote server reportedly hosts a sophisticated command and control system that the attacker can use to control infected systems via a web interface.