Trojan:W32/Cerber

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.

Consequences

Based 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:

• US-CERT (March 31, 2016): Alert (TA16-091A) Ransomware and Recent Variants
• Article: Crypto-ransomware