alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Bitter APT CHM CnC Activity (GET) M1"; flow:established,to_server; http.method; content:"GET"; http.uri; content:".php?st="; offset:10; depth:16; fast_pattern; content:"|2a|"; distance:0; http.user_agent; content:"Windows Installer"; bsize:17; reference:md5,313bee67ac85d0aed3fbd049f9d2b0e3; reference:url,twitter.com/Jup1a/status/1569578703289720837; reference:md5,16696b82884de21b3ef5a3b27872d53c; classtype:trojan-activity; sid:2038820; rev:2; metadata:attack_target Client_Endpoint, created_at 2022_09_01, deployment Perimeter, malware_family Sidewinder, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_01_31, reviewed_at 2025_10_24;)