alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Phantom Captcha Fake Chrome User-Agent Observed"; flow:established,to_server; http.user_agent; bsize:115; content:"Mozilla|2f|5|2e|0|20 28|Windows|20|NT|20|10|2e|0|3b 20|Win64|3b 20|x64|29 20|AppleWebKit|2f|534|2e|36|20 28|KHTML|2c 20|like|20|Gecko|29 20|Chrome|2f|95|2e|4|2e|4476|2e|124|20|Safari|2f|537|2e|36"; reference:url,sentinelone.com/labs/phantomcaptcha-multi-stage-websocket-rat-targets-ukraine-in-single-day-spearphishing-operation; reference:md5,61660f072008998bf57f8ad602408b68; classtype:command-and-control; sid:2065338; 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_10_23, deployment Perimeter, deployment SSLDecrypt, confidence High, signature_severity Critical, tag c2, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2025_10_23, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1071, mitre_technique_name Application_Layer_Protocol; target:src_ip;)