ET ATTACK_RESPONSE ASP.NET Web BackDoor Webshell Title Banner Observed

alert http $EXTERNAL_NET any -> $HOME_NET any (
    msg:"ET ATTACK_RESPONSE ASP.NET Web BackDoor Webshell Title Banner Observed";
    flow:established,to_client;
    http.stat_code;
    content:"200";
    http.response_body;
    content:"|3C|title|3E|ASP.NET Web BackDoor|3C|/title|3E|"; fast_pattern;
    reference:url,github.com/tennc/webshell/blob/master/net-friend/aspx/Aspx%EF%BC%88%E5%85%8D%E6%9D%80%EF%BC%89.aspx;
    reference:url,blog.talosintelligence.com/uat-8099-chinese-speaking-cybercrime-group-seo-fraud/;
    classtype:trojan-activity;
    sid:2068142; rev:1;
    metadata:affected_product Microsoft_IIS, attack_target Web_Server, tls_state TLSDecrypt, created_at 2026_03_10, deployment Perimeter, malware_family Web_BackDoor, performance_impact Low, confidence High, signature_severity Major, tag WebShell, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2026_03_10, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1105, mitre_technique_name Ingress_Tool_Transfer;
    target:src_ip;
)