alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Lumma Stealer Victim Fingerprinting Activity"; flow:established,to_server; http.uri; content:"/api/set_agent?id="; startswith; fast_pattern; pcre:"/^[A-Z0-9]{32}/R"; content:"&token="; within:8; content:"&description="; distance:0; content:"&agent="; distance:0; threshold:type limit,count 1,seconds 300,track by_src; reference:url,trendmicro.com/en_us/research/25/k/lumma-stealer-browser-fingerprinting.html; reference:url,malware-traffic-analysis.net/2026/01/01/index.html; classtype:command-and-control; sid:2066606; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, tls_state TLSDecrypt, created_at 2026_01_06, deployment Perimeter, deployment SSLDecrypt, malware_family Lumma_Stealer, confidence High, signature_severity Critical, tag c2, updated_at 2026_01_06, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1071, mitre_technique_name Application_Layer_Protocol; target:src_ip;)