Detect Exchange Web Shell Creation

This analytic identifies the creation of suspicious .aspx or .ashx files in known drop locations for Exchange exploitation. Specifically, it targets paths associated with HAFNIUM group activity and vulnerabilities like ProxyShell and ProxyNotShell. This activity is a strong indicator of web shell deployment, a common method for persistent access and remote code execution. Successful exploitation could lead to unauthorized access, arbitrary command execution, and privilege escalation within the Exchange environment.