Threat Descriptons



Category :


Type :


Aliases :

Cerber.[variant], Trojan.Ransom.Cerber.[variant], Trojan-Downloader:W97M/Cerber.[variant]


Cerber variants are ransomware that encrypt the device or data stored on it, then demand a payment from the user to restore normal access to the affected content or device.


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.

Further action

If 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.

Technical Details

Users may encounter Cerber ransomware in a number of ways:

  • When browsing a legitimate website that has been compromised to host harmful files
  • When redirected by another threat to a malicious or fake website that hosts the harmful files
  • When silently dropped on the user's machine by an exploit kit or botnet
  • As a file attached to a spam or targeted email

Cerber ransomware will often use social engineering. This usually involves making the file, spam email or fake website look legitimate or desirable enough to lure the user into voluntarily running the file.

Once launched, the ransomware will silently encrypt files on a computer, essentially 'scrambling' the contents of the file so that the user can't access it normally without a decryption key that can correctly 'unscramble' it. This type of ransomware is known as crypto-ransomware.


Depending on the type of ransomware involved, the user may be able to take further actions. In most cases however, the encryption used to hold the content or computer hostage is extremely difficult to break, making recovery impossible unless a) a clean, recent backup is available, or b) the decryption key is obtained.

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. Precautionary measures should also be taken to protect your content and machine from being vulnerable to ransomware in the future. For more information, see:

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