What is WannaCry?

WannaCry is a type of ransomware that emerged in May 2017 and quickly spread across the globe, affecting hundreds of thousands of computers in more than 150 countries. It is known for exploiting a vulnerability in Windows operating systems called EternalBlue, which was allegedly developed by the U.S. National Security Agency (NSA) and leaked by a group known as the Shadow Brokers.

Features of WannaCry:

1. Ransomware Behavior: Once infected, WannaCry encrypts the files on the victim’s computer, making them inaccessible. The malware then displays a ransom note demanding payment in Bitcoin in exchange for a decryption key that would unlock the files.

2. Propagation Mechanism: WannaCry spreads rapidly by using the EternalBlue exploit to target vulnerable versions of Windows. This allowed it to move laterally within networks without requiring user interaction.

3. Kill Switch: A researcher inadvertently discovered a “kill switch” in the code, which significantly slowed the spread of WannaCry. The kill switch was a hardcoded domain that, when registered, stopped the malware from propagating further.

4. Impact: WannaCry affected many high-profile organizations, including hospitals in the UK’s National Health Service (NHS), telecom companies, and manufacturing firms. The disruption led to canceled medical procedures, halted production lines, and financial losses.

Preventive Measures:

• Patch Management: Ensure that all systems are up to date with the latest security patches to prevent exploitation of known vulnerabilities like EternalBlue.

• Backups: Regularly back up important data to ensure that, in the case of an attack, systems can be restored without paying the ransom.

• Antivirus and Firewalls: Use robust antivirus software and configure firewalls to detect and block ransomware activities. 

• User Awareness: Educate users about the risks of phishing emails and malicious attachments, which are common vectors for ransomware delivery.

WannaCry was a significant wake-up call to the global community about the importance of proactive cybersecurity practices.