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

• 567407d941d99abeff20a1b836570d30

SHA-256

• a0dccbe010859116063fc3f7e00c8c7bd68b849eeb7238a10b1b9f07f5c36510

SHA-1

• e8866fda01f91c6d4bf8c51cf4cbc7f103e87b0b

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.