alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET INFO Suspected Phishing Simulation Related Request (GET)"; flow:established,to_server; urilen:9; http.method; content:"GET"; http.uri; pcre:"/^\/[A-Za-z]{3}-[A-Za-z0-9]{4}$/"; http.header_names; content:!"Referer"; http.user_agent; content:"|3b 20|ms-office|3b 20|"; http.host; content:".com-office365.com"; endswith; fast_pattern; reference:md5,6c53f4d178b55d1deb4b1385d5efb1a9; reference:md5,13e25a506a7282762c46adfd408cdb94; classtype:bad-unknown; sid:2042539; rev:1; metadata:attack_target Client_Endpoint, created_at 2022_12_09, deployment Perimeter, confidence High, signature_severity Informational, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2022_12_09; target:src_ip;)