Trojan:W32/Agent.AF.A "locks" the machine and displays a message directing the user to send an SMS to a specified number in order to receive the password key to unlock the computer.
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.
Agent.AF may be considered ransomware as it hijacks the computer system and demands the user perform a specified action in order to regain control of the machine. Agent.AF may be dropped on a computer by Trojan-Dropper:W32/Blocker.A..
Agent.AF installs to the Windows temp folder. All samples analyzed so far show that the file uses the filename:
where X is a number.The trojan then modifies the UserInit registry by adding a file path to the said registry so that it executes automatically.
Note: The default value of this key is Userinit = %systemfolder%\userinet.exe
To take control of the computer, Agent.AF drop a batch file that forces the machine to reboot. During reboot, the batch file "locks" the computer screen. At the same time, it disables several Windows shortcut key combinations to prevent the user from regaining control over the machine, including CTRL+ALT+DEL, Alt+F4 and others.The trojan then displays the following message in a small window in the center:
The message directs the user to send an SMS containing a number key (generated by the malware) to the number 3649.