Richard Beck | 15 May 2017
The ransomware, which is associated to the names WannaCry, WanaCrypt, WanaCrypt0r, WCry, and Wanna Decryptor, has infected thousands of machines worldwide. It spreads, like a worm, exploiting a Microsoft Windows vulnerability, scanning on a legacy network communication protocol Server Message Block (SMB) targeting computers that have not yet patched the exploited vulnerability. Ransomware works by encrypting the files on the compromised computer, which makes them inaccessible. The malware then requests a payment of $300 worth of the digital currency known as Bitcoin. Delayed payment within the specified timeframe results in an increased ransom penalty. Non-payment usually results in the loss of access to the encrypted files, forever.
What can I do now?
- Apply the Windows patch released on the 14th March (this will not help those machines already compromised).
- Prevent WannaCry from communicating on your network, block inbound traffic on SMB (ports 139, 445).
- Block connections to the anonymisation network Tor and specifically the Tor nodes and known Tor exit nodes.
- Update the rule base on your Intrusion Detection/Prevention (IDS/IPS) or firewall platforms with the publicly available Indicators of Compromise (IoC), Command and Control (CnC) and hash values for WannaCry.
What should I be doing next?
There are over 50 ransomware families, with some 300 strains, prepare for new variants of WannaCry which will appear in the wild this month.
- Review your backup strategy, back up your data and key platforms regularly. If you become a ransomware victim, restore your files from a backup instead of paying the ransom.
- Test your backup process. Practice recovery of backups and enterprise data centric platforms, which are at high risk to you.
- Install patches and updates immediately, subject to your patch testing processes. Many victims of ransomware are using outdated or unprotected operating systems.
- Install strong anti-virus and anti-malware software and keep it updated with the latest virus and malware definitions
- Educate your staff about Cyber hygiene and Phishing awareness, they will be the gateway for a future cyber-attack on your business.
- Take care when clicking links in emails.
- Exercise extreme caution when opening any email attachment. Think before you click!
- Take an extra moment to check unexpected emails you receive — even from trusted sources.
The National Cyber Security Centre (NCSC) threat guidance page will provide the latest up to date information on this Ransomware threat.