To help keep your devices safe against ransomware attacks, such as Petya, back up your data regularly, make sure automatic updates are turned on, and your devices are up to date.
- In Windows 10, go to Settings > Update & Security. You'll see your update status there.
- In Windows 8.1, go to Settings > Change PC Settings > Update and recovery.
- In Windows 7, go to Control Panel > Windows Update.
If your update status says that your device is up to date, then you're all set. Otherwise, Microsoft recommends you immediately install Microsoft Security Bulletin MS17-010.
Ransomware is computer malware that restricts access—or even stops you from using your PC—or encrypts your files. It then tries to force you into paying money (a ransom) to regain access to them.
Some of the ways you can get infected by ransomware include:
- Visiting unsafe, suspicious, or fake websites.
- Opening emails and email attachments that you weren’t expecting or from people you don’t know.
- Opening malicious or bad links in emails, Facebook, Twitter, and other social media posts, or in instant messenger chats, like Skype.
You can often recognize a fake email and webpage because they have bad spelling, or just look unusual. Look out for strange spellings of company names (like "PayePal" instead of "PayPal") or unusual spaces, symbols, or punctuation (like "iTunesCustomer Service" instead of "iTunes Customer Service").
Ransomware can target any PC—whether it’s a home computer, PCs on an enterprise network, or servers used by a government agency.
How can I help keep my PC secure?
Whether you’ve just bought a new PC or you’re using the same one you’ve had, there are some ways in which you can try to keep it more secure:
- Make sure your PC is up to date with the latest version of Windows. Learn more about Windows Update.
- Turn on Windows Defender Antivirus to help protect you from viruses and malware.
- Turn on File History if it hasn’t already been turned on by your PC’s manufacturer. Learn more about File History.
- Back up the content on your PC regularly. Learn more about backing up your files.
- Take advantage of storage space to maintain two copies of your PC data. Learn more about storage space.
If you suspect you’ve been infected
Use antimalware programs, such as Windows Defender Antivirus, whenever you’re concerned your PC might be infected—for example, if you hear about a new malware in the news or you notice odd behavior on your PC. Learn more about Windows Defender Antivirus.
If you actually get a ransomware infection
Unfortunately, a ransomware infection doesn’t show itself until you see some type of notification, either in a window, an app, or a full-screen message, demanding money to regain access to your PC or files. These messages often display after encrypting your files.
Try fully cleaning your PC with Windows Defender Offline. You should do this before you try to recover your files. Also see Backup and Restore in Windows 10 for help on backing up and recovering files for your version of Windows.
Do not pay any money to recover your files. Even if you were to pay the ransom, there is no guarantee that you will regain access to your PC or files.
What to do if you already paid
If you’ve already paid the ransom, immediately contact your bank and your local authorities. If you paid with a credit card, your bank may be able to block the transaction and return your money.
You can also contact the following government fraud and scam reporting websites:
- In Australia, go to the SCAMwatch website.
- In Canada, go to the Canadian Anti-Fraud Centre.
- In France, go to the Agence nationale de la sécurité des systèmes d'information website.
- In Germany, go to the Bundesamt für Sicherheit in der Informationstechnik website.
- In Ireland, go to the An Garda Síochána website.
- In New Zealand, go to the Consumer Affairs Scams website.
- In the United Kingdom, go to the Action Fraud website.
- In the United States, go to the On Guard Online website.
If your country or region isn't listed here, Microsoft recommends that you contact your country or region's federal police or communications authority.
For an illustrated overview about ransomware and what you can do to help protect yourself, see The 5Ws and 1H of ransomware.
If you're in an enterprise, see the Microsoft Malware Protection Center for in-depth information about ransomware.