alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET HUNTING Suspicious Header Name In HTTP Request (U)"; flow:established,to_server; http.header_names; content:"|0d 0a|U|0d 0a|"; reference:md5,b3b735852084909f82121fd6fbbdeb68; classtype:misc-activity; sid:2053436; rev:1; metadata:attack_target Client_Endpoint, tls_state TLSDecrypt, created_at 2024_06_10, deployment Perimeter, deployment SSLDecrypt, confidence Low, signature_severity Informational, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_06_10, reviewed_at 2025_04_21;)