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A potentially malicious web request was executed against a web server

Detects unobstructed Web Application Firewall (WAF) activity in sessions where the WAF blocked incoming requests by computing the ratio between blocked requests and unobstructed WAF requests in these sessions…

Description

Detects unobstructed Web Application Firewall (WAF) activity in sessions where the WAF blocked incoming requests by computing the ratio between blocked requests and unobstructed WAF requests in these sessions (BlockvsSuccessRatio metric). A high ratio value for a given client IP and hostname calls for further investigation of the WAF data in that session, due to the significantly high number of blocked requests and a few unobstructed logs that may be malicious but have passed undetected through the WAF. The successCode variable defines what the detection thinks is a successful status code and should be altered to fit the environment.

Detection logic

Detection requirements

Platform
ContainersESXiIaaSLinuxmacOSNetwork DevicesWindows

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

Log source product
waf
Log source service
azurediagnostics

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