Windows Security Software Had a Flaw That Let Ransomware Through. Update Now.

Microsoft Defender, the security software built into Windows computers, had a serious vulnerability that criminals exploited to launch ransomware attacks. This flaw was being used by hackers before Microsoft could release a fix, which is known as a zero day (a newly discovered software flaw with no fix yet) attack.

Ransomware locks your files and demands payment to unlock them. This affects anyone using Windows computers with Microsoft Defender. Since Defender comes automatically with Windows, this includes most home users, families, and businesses running Windows.

The criminals used this weakness to bypass the very software designed to protect your computer from threats like ransomware.

1. Update Windows immediately. Go to Settings, then Windows Update, and click Check for Updates. Install all available updates, especially security updates.
2. Restart your computer after updates finish installing. Many security patches only take effect after a restart.
3. Make sure Windows is set to install updates automatically. In Windows Update settings, enable automatic updates so you receive future fixes right away.
4. Back up your important files to an external hard drive or cloud service today. If ransomware does strike, backups let you restore your files without paying criminals. Going forward, maintain regular backups of your photos, documents, and other irreplaceable files. Keep your backup drive disconnected when not in use, so ransomware cannot encrypt it along with your computer. Train family members to recognize suspicious emails and links, since these are common ways ransomware gets installed. Regular updates and backups are your best defense against these attacks.