alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE AlphaCrypt CnC Beacon 3"; flow:established,to_server; urilen:>250; http.method; content:"GET"; http.uri; content:"/r.php?"; fast_pattern; pcre:"/\/r\.php\?[A-F0-9]+=?$/"; http.header_names; content:!"|0d 0a|Accept"; content:!"|0d 0a|Referer|0d 0a|"; content:"|0d 0a|User-Agent|0d 0a|"; startswith; reference:md5,0a4d0e5d0b69560414bbd20127bd8176; classtype:command-and-control; sid:2021723; rev:7; metadata:attack_target Client_Endpoint, created_at 2015_08_27, deployment Perimeter, signature_severity Major, tag c2, updated_at 2024_03_11, mitre_tactic_id TA0010, mitre_tactic_name Exfiltration, mitre_technique_id T1041, mitre_technique_name Exfiltration_Over_C2_Channel;)