Aliases: Troj/Ransom-CJM (Sophos) Trojan.Cryptolocker.AH (Symantec)
Windows Defender Antivirus detects and removes this threat.
This ransomware can stop you from using your PC or accessing your data. It might ask you to pay money to a malicious hacker.
Our ransomware FAQ page has more information on this type of threat.
The trend towards increasingly sophisticated malware behavior, highlighted by the use of exploits and other attack vectors, makes older platforms so much more susceptible to ransomware attacks. From June to November 2017, Windows 7 devices were 3.4 times more likely to encounter ransomware compared to Windows 10 devices.
There is no one-size-fits-all response if you have been victimized by ransomware. There is no guarantee that paying the ransom will give you access to your files.
If you've already paid, see ransomware page for help on what to do now.
Run antivirus or antimalware software
Use the following free Microsoft software to detect and remove this threat:
- Windows Defender for Windows 8.1 and Windows 10, or Microsoft Security Essentials for Windows 7 and Windows Vista
- Microsoft Safety Scanner
You should also run a full scan. A full scan might find hidden malware.
You can also ask for help from other PC users at the Microsoft virus and malware community.
If you’re using Windows XP, see our Windows XP end of support page.
Use cloud protection
Use cloud protection to help guard against the latest malware threats. It’s turned on by default for Microsoft Security Essentials and Windows Defender for Windows 10.
To check if it's running, go to All settings > Update & security > Windows Defender and make sure that your Cloud-based Protection settings is turned On.