alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET WEB_SERVER Suspected FOXSHELL Variant Webshell Activity"; flow:established,to_client; http.response_body; content:"200"; fast_pattern; startswith; pcre:"/^\n(?:[0-9A-F]{118})\n$/R"; reference:md5,126bc1c30fba27f8bf67dce4892b1e8c; reference:url,research.checkpoint.com/2023/from-albania-to-the-middle-east-the-scarred-manticore-is-listening/; classtype:trojan-activity; sid:2049011; rev:1; metadata:attack_target Server, created_at 2023_11_01, deployment Perimeter, confidence Medium, signature_severity Major, tag WebShell, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2023_11_03, reviewed_at 2023_11_01, mitre_tactic_id TA0003, mitre_tactic_name Persistence, mitre_technique_id T1505, mitre_technique_name Server_Software_Component; target:src_ip;)