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ProxyShell ProxyNotShell Behavior Detected

The following analytic identifies potential exploitation of Windows Exchange servers via ProxyShell or ProxyNotShell vulnerabilities, followed by post-exploitation activities such as running nltest, Cobalt Strike,…

Description

The following analytic identifies potential exploitation of Windows Exchange servers via ProxyShell or ProxyNotShell vulnerabilities, followed by post-exploitation activities such as running nltest, Cobalt Strike, Mimikatz, and adding new users. It leverages data from multiple analytic stories, requiring at least five distinct sources to trigger, thus reducing noise. This activity is significant as it indicates a high likelihood of an active compromise, potentially leading to unauthorized access, privilege escalation, and persistent threats within the environment. If confirmed malicious, attackers could gain control over the Exchange server, exfiltrate data, and maintain long-term access.

Detection logic

Detection requirements

Platform
ContainersESXiIaaSLinuxmacOSNetwork DevicesWindows

The rule states no platform. This is derived from the 2 ATT&CK techniques it maps to.

Known benign triggers

  • False positives will be limited, however tune or modify the query as needed.

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