Detections
Explore public detection logic contributed by the community across SIEM and rule languages.
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Detects anomalous child process execution (e.g., cmd.exe, powershell.exe) by the Microsoft Exchange IIS worker process (w3wp.exe) or the creation of .aspx files in Exchange web directories. This behavior is highly indicative of post-exploitation activity, such as web shell deployment, frequently observed in attacks targeting vulnerabilities like ProxyShell and ProxyLogon.
This rule detects potential successful exploitation of CVE-2021-26857, a Microsoft Exchange Server vulnerability. It specifically looks for abnormal child processes spawning from the 'UMWorkerProcess.exe' (Unified Messaging service) on Exchange servers. The rule filters out legitimate Windows Error Reporting processes ('wermgr.exe' and 'WerFault.exe') to reduce false positives, indicating that any other process spawned by 'UMWorkerProcess.exe' is considered suspicious and a potential indicator of compromise.
