Rewterz Threat Alert – Ryuk Ransomware – Active IOCs

Severity

High

Analysis Summary

Ryuk Ransomware is a ransomware family that was first found in the wild in August 2018. It is one of the most virulent ransomware strains on the market. Ryuk has been observed being used to attack companies or professional environments. This ransomware can lock your files or systems and hold them hostage for ransom. Ryuk targets high-profile enterprises in order to obtain essential information that will impair the victim’s operations.

Ryuk is a form of ransomware used in targeted attacks, in which threat actors encrypt important data to demand big ransom payments. Emotet or TrickBot malware is widely used to spread Ryuk ransomware. Ryuk’s code is comparable to that of the Hermes ransomware. The Ryuk ransomware is believed to be operated by the Russian cybercriminal group WIZARD SPIDER.

Impact

• File encryption
• Privilege Escalation 
• Information Theft 
• Data Exfiltration 
• Network Compromise

Indicators of Compromise

MD5

• fdbb72a18e8e6e029482ee72d900f24a

SHA-256

• e74567b575ff61b948ca3e4d41c2a488c67f09bcc29de5e35302716d63796c54

SHA-1

• cb91a69f6beb5cc62778fc6d72ab4da2eb1bfd06

Remediation

• Block all threat indicators at your respective controls.
• Search for IOCs in your environment.
• Maintain cyber hygiene by updating your anti-virus software and implementing a patch management lifecycle.
• Maintain Offline Backups – In a ransomware attack, the adversary will often delete or encrypt backups if they have access to them. That’s why it’s important to keep offline (preferably off-site), encrypted backups of data and test them regularly.
• Emails from unknown senders should always be treated with caution.
• Never trust or open ” links and attachments received from unknown sources/senders.