There are other situations where security researchers take control of command-and-control servers used by the ransomware authors and make the decryption keys available to users for free. Unfortunately these cases are even rarer than vulnerabilities in the ransomware programs themselves.
Most security vendors discourage paying the ransom, because there's no guarantee that the attackers will provide the decryption key and because it ultimately encourages them.
If you decide to hold your ground, keep a copy of the affected files as you never know what might happen in the future. However, if those files are critical to your business and their recovery is time sensitive, there's little you can do other than pay up and hope that the criminals keep their word.
Prevention is best
Ransomware programs get distributed in a variety of ways, most commonly through malicious email attachments, Word documents with macro code and Web-based exploits launched from compromised websites or malicious advertisements. Many are also installed by other malware programs.
As such, following the most common security best practices is critical. Always keep the software on your computer up to date, especially the OS, browser and browser plug-ins like Flash Player, Adobe Reader, Java and Silverlight. Never enable the execution of macros in documents, unless you have verified their senders and have confirmed with them that the documents should contain such code. Carefully scrutinize emails, especially those that contain attachments, regardless of who appears to have sent them. Finally, perform your day-to day activities from a limited user account, not from an administrative one, and run an up-to-date antivirus program.
Sign up for CIO Asia eNewsletters.