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Microsoft Security Intelligence
Published May 24, 2017 | Updated Jan 10, 2018

Ransom:Win32/Jaffrans

Detected by Microsoft Defender Antivirus

Aliases: No associated aliases

Summary

Microsoft 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 (in the form of Bitcoins) to a malicious hacker.

Your PC can get infected with this ransomware from malicious attachments in spammed email messages. The email messages carry a .pdf file attachment embedded with a document containing malicious macro codes. When the attachment is opened, the malicious macro downloads this ransomware from multiple server locations.

This ransomware encrypts files on your computer. It appends any of the following file name extensions to encrypted files: .jaff, .wlu, or .sVn.

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.

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 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.

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 Microsoft Defender Antivirus for Windows 10. 

Go to Settings > Update & security > Windows Defender > Windows Defender Security Center > Virus & threat protection and make sure that your Cloud-based Protection settings is turned On.

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