ET RETIRED Win32/Fewin Stealer Data Exfiltration Attempt

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"ET RETIRED Win32/Fewin Stealer Data Exfiltration Attempt";
    flow:established,to_server;
    http.method;
    content:"POST";
    http.uri;
    content:"/Up/b"; bsize:5;
    http.content_type;
    content:"application/octet-stream|3b 20|boundary|3d 2d 2d 2d 2d|";
    http.request_body;
    content:"PK"; startswith;
    content:"1/0/cert"; fast_pattern; within:100;
    reference:md5,56b7f9a65fbab95e2c854b96c68ffee2;
    reference:md5,abceb35cf20f22fd8a6569a876e702cb;
    classtype:trojan-activity;
    sid:2049140; rev:3;
    metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, affected_product Windows_11, attack_target Client_Endpoint, created_at 2023_11_09, deployment Perimeter, former_category MALWARE, malware_family Stealer, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2025_04_17, reviewed_at 2025_04_17, mitre_tactic_id TA0009, mitre_tactic_name Collection, mitre_technique_id T1005, mitre_technique_name Data_from_local_system;
    target:src_ip;
)