ET MALWARE Ursnif Variant CnC Beacon

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"ET MALWARE Ursnif Variant CnC Beacon";
    flow:established,to_server;
    urilen:>125;
    http.method;
    content:"GET";
    http.uri;
    content:"/assets/"; fast_pattern;
    content:"."; distance:100;
    pcre:"/\/assets(?:\/[a-zA-Z0-9_]+)+\.(?:jpeg|gif)$/";
    http.header_names;
    content:!"Accept";
    content:!"Referer|0d 0a|";
    http.user_agent;
    pcre:"/^(?:Mozilla\/|Shockwave)/i";
    reference:md5,4dbff312f5ee5bfbd757030109faec2d;
    classtype:command-and-control;
    sid:2023870; rev:4;
    metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2017_02_06, deployment Perimeter, malware_family ursnif, performance_impact Significant, confidence High, signature_severity Major, tag c2, updated_at 2024_04_22, mitre_tactic_id TA0010, mitre_tactic_name Exfiltration, mitre_technique_id T1041, mitre_technique_name Exfiltration_Over_C2_Channel;
)