Microsoft security software detects and removes this threat.

This ransomware locks your PC and shows a full-screen message, commonly called a "lock screen".

It tries to convince you to pay a fine by claiming your PC has been used for illegal activities without your knowledge. The message is a fraud.

What to do now

Microsoft doesn’t recommend you pay the fine. There is no guarantee that paying the ransom will give you access to your files.

If you've already paid, see our 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:

You should also run a full scan. A full scan might find hidden malware.

Advanced troubleshooting

To restore your PC, you might need to download and run Windows Defender Offline. See our advanced troubleshooting page for more help.

Get more help

You can also visit our advanced troubleshooting page or search the Microsoft virus and malware community for more help.

If you’re using Windows XP, see our Windows XP end of support page.

Threat behavior

Ransom:JS/Krypterade.A tries to extort money by blackmailing you with a claim that a crime was committed using your PC.

It uses a lock screen to stop you from accessing your files or documents. It then tells you to pay a fine to get control of your PC back.

It also stops you from viewing the web page source code and from selecting or copying text.

The language of the lock screen message and the payment options can vary depending on your location.

The images below are some examples of the messages shown by Ransom:JS/Krypterade.A:

Analysis by Vincent Tiu


The following could indicate that you have this threat on your PC:

  • You see any of these messages:



Alert level: Severe
First detected by definition: 1.165.1328.0
Latest detected by definition: 1.175.355.0 and higher
First detected on: Jan 07, 2014
This entry was first published on: Feb 10, 2014
This entry was updated on: Sep 21, 2015

This threat is also detected as:
  • JS/Phish (AVG)
  • W32/Ransom.AFD!tr (Fortinet)
  • JS/Redirector (McAfee)
  • Troj/Ransom-AFD (Sophos)