alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE TA416 PlugX CnC Activity (GET)"; flow:established,to_server; http.method; content:"GET"; http.uri; content:"|3f|t|3d|"; pcre:"/^\d{10}\x26/R"; pcre:"/\x3d[a-zA-Z0-9]{5,25}$/"; http.header; content:"Cache|2d|Control|3a 20|no|2d|cache|0d 0a|Connection|3a 20|Keep|2d|Alive|0d 0a|Pragma|3a 20|no|2d|cache|0d 0a|Accept|3a 20 2a 2f 2a 0d 0a|If|2d|None|2d|Match|3a 20|"; http.header_names; bsize:128; content:"|0d 0a|cache-control|0d 0a|connection|0d 0a|pragma|0d 0a|accept|0d 0a|if-none-match|0d 0a|user-agent|0d 0a|sec-fetch-dest|0d 0a|sec-fetch-site|0d 0a|sec-fetch-mode|0d 0a|host|0d 0a 0d 0a|"; nocase; fast_pattern; threshold:type limit,count 1,seconds 300,track by_src; classtype:command-and-control; sid:2068412; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, tls_state TLSDecrypt, created_at 2025_11_10, deployment Perimeter, deployment SSLDecrypt, confidence High, signature_severity Critical, tag c2, tag TA416, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2026_03_25, former_sid 2865138, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1071, mitre_technique_name Application_Layer_Protocol; target:src_ip;)