Trojan:W32/Nymaim is ransomware that is also capable of downloading additional malware onto the affected device.
F-Secure detects ransomware using a variety of signature and generic detections. Once detected, the F-Secure security product will automatically remove the file.
If the ransomware uses encryption to take files or an entire system hostage, the encryption may be sufficient to make it very difficult to decrypt the files without the necessary decryption key. In such circumstances, the recommended course of action is to report the crime to the relevant authorities and restore the affected data from a backup.
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.
Trojan:W32/Nymaim has been found to be delivered via exploit kits, or in files (typically using filenames related to popular keyword searches) that are downloaded from various malicious websites.
If Nymaim is launched on a device, it will attempt to either lock the screen or download additional malware. If the user is located in a country in Europe or North America, the malware will download a customized lockscreen for that particular country; the lockscreen will display the ransom demand. If the user is in a country for which no customized lockscreen is available, Nymain will download a second-stage component which can be used at a later time to download additional malware.