Rewterz Threat Alert – Ryuk Evolved Its Encryption and Evasion Techniques

Severity

High

Analysis Summary

A string of high profile attacks has been detected that have been crippling companies. The current waves of attacks have been known to use a combination of Emotet, Trickbot, and Ryuk. In recent weeks, the actors behind Ryuk have even been observed using ZeroLogon to extend their reach and broaden the delivery of their ransomware payloads. The current waves of attacks have been known to use a combination of Emotet, Trickbot, and Ryuk. While the Ryuk payloads do not specifically contain the ZeroLogon functionality, the flaw is being leveraged at earlier stages in the attack chain. Attackers are able to use existing capabilities in Cobalt Strike and similar frameworks to achieve the privilege escalation. It is quickly becoming clear that ZeroLogon will become a staple in the attackers’ collective “toolbelt”.

Impact

• Privilege Escalation 
• Information Theft 
• Data Exfiltration 
• Files Encryption 
• Network Compromise

Indicators of Compromise

MD5

• c0202cf6aeab8437c638533d14563d35
• 437262fa4eaf6c91c40a40789ae11d33
• 7d3f19b760cb1958a2c4d9ca7492c406

SHA-256

• 8d3f68b16f0710f858d8c1d2c699260e6f43161a5510abb0e7ba567bd72c965b
• 7e28426e89e79e20a6d9b1913ca323f112868e597fcaf6b9e073102e73407b47
• f8bc1638ec3b04412f708233e8586e1d91f18f6715d68cba1a491d4a7f457da0

SHA1

• 5767653494d05b3f3f38f1662a63335d09ae6489
• 4020a6863b53456bcc53140339b6312e004d53d5
• c3fa91438850c88c81c0712204a273e382d8fa7b

Remediation

• Block the threat indicators at their respective controls.
• Immediately patch the ZeroLogon vulnerability if it hasn’t been patched already.
• Do not download files attached in untrusted emails.
• Maintain a strong password policy and implement multifactor authentication where possible.