Rewterz Threat Alert – Ryuk Ransomware – Active IOCs

Severity

High

Analysis Summary

Ryuk is the name of a ransomware family, first discovered in the wild in August 2018. It is one of the nastiest ransomware going around. Ryuk will lock your files or systems and holds them hostage for ransom. Ryuk is a type of ransomware used in targeted attacks, where the threat actors make sure that essential files are encrypted so they can ask for large ransom amounts. A typical Ryuk ransom demand can amount to a few hundred thousand dollars. Ryuk is one of the first ransomware families to include the ability to identify and encrypt network drives and resources, as well as delete shadow copies on the endpoint. This means the attackers can then disable Windows System Restore for users, making it impossible to recover from an attack without external backups.

Ryuk is delivery method is spam emails. These emails are often sent from a spoofed address, so the sender name does not raise suspicion.

Impact

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

Indicators of Compromise

MD5

• 91d9387faefce8305cce6d50fcf5fa69

SHA-256

• 42b0b731d85e5444a87e147a404ac57be34bf87b40294cb2d4664f9a2aaa0e3f

SHA1

• 2ac56820125a852022fa392a3947f18ef87159f4

Remediation

• Block all threat indicators at your respective controls.
• Search for IOCs in your environment.