A trojan, or trojan horse, is a seemingly legitimate program which secretly performs other, usually malicious, functions. It is usually user-initiated and does not replicate.
Once detected, the F-Secure security product will automatically disinfect the suspect file by either deleting it or renaming it.
Trojan:W32/Daonol.gen!C is the Generic Detection for a program that steals information from the user, including passwords.
The malware adds the following file to the parent directory of where it was executed:
- %cwd%\...\[random filename]
For example, if the program is run in C:\Windows\System32, the file is dropped in C:\Windows.
The malware then creates this registry :
- HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Drivers32 aux[n+1] = [path to random filename]
Where n is the existing number of aux (e.g., if your machine originally has aux and aux2 the malware will create aux3)
Once the trojan has executed (and delivered its payload), it deletes itself.
Once installed, Daonol will inject itself into system processes and steal information, including passwords, from the user.
It will also blocks execution of regedit and bat files.
If the file dropped by the trojan is manually deleted by the user, it is automatically restored by the injected processes.
As the malware prevents execution of the regedit file, not being able to run regedit can be taken as a sign the computer may be infected.
About Generic Detections
Unlike more traditional detections (also known as signatures or single-file detections) a Generic Detection does not identify a unique or individual malicious program. Instead, a Generic Detection looks for broadly applicable code or behavior characteristics that indicate a file as potentially malicious, so that a single Generic Detection can efficiently identify dozens, or even hundreds of malware.
For more information about Generic Detections, see the the Generic Detection description.