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Microsoft Security Intelligence
Published Jan 06, 2017 | Updated Jan 10, 2018

Ransom:Win32/Firecrypt.A

Detected by Microsoft Defender Antivirus

Aliases: No associated aliases

Summary

Windows Defender AV detects and removes this threat.

This ransomware searches for certain types of files and encrypts these files. It renames the encrypted files by appending the new extension name .firecrypt. For example, after it encrypts the file example.doc, it renames this file to example.doc.firecrypt.

Encrypted files are inaccessible unless victims pay a fee to attackers. We have samples that include a ransom note instructing victims to send bitcoins to an attacker-controlled email address.

This ransomware also attempts to connect to a legitimate website as part of a denial-of-service (DoS) attack against that site.

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.

Read our latest report: A worthy upgrade: Next-gen security on Windows 10 proves resilient against ransomware outbreaks in 2017.

Microsoft doesn’t recommend you pay the ransom. 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.

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. 

Go to All settings > Update & security > Windows Defender and make sure that your Cloud-based Protection settings is turned On.

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