ET MALWARE Ursa Loader CnC Checkin

Query · suricata

flow:established,to_server;
urilen:1;
http.method;
content:"POST";
http.user_agent;
content:"Mozilla/3.0 (compatible|3b 20|Indy Library)"; fast_pattern;
http.request_body;
pcre:"/^[a-z]{1,10}=[A-Z]+(?:&[a-z]{1,10}=[A-Z]+){2,}$/s";
http.request_line;
content:"POST / HTTP/1.0"; depth:15; endswith;
http.content_type;
content:"application/x-www-form-urlencoded";
http.header_names;
content:!"Referer";
Raw source ET MALWARE Ursa Loader CnC Checkin · Suricata
Esc
Published by Emerging Threats Open ↗, licensed under BSD 3-Clause ↗. Line breaks added for readability; the rule is otherwise unchanged. 
alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"ET MALWARE Ursa Loader CnC Checkin";
    flow:established,to_server;
    urilen:1;
    http.method;
    content:"POST";
    http.user_agent;
    content:"Mozilla/3.0 (compatible|3b 20|Indy Library)"; fast_pattern;
    http.request_body;
    pcre:"/^[a-z]{1,10}=[A-Z]+(?:&[a-z]{1,10}=[A-Z]+){2,}$/s";
    http.request_line;
    content:"POST / HTTP/1.0"; depth:15; endswith;
    http.content_type;
    content:"application/x-www-form-urlencoded";
    http.header_names;
    content:!"Referer";
    reference:md5,d05af060e3e104dea638f17c4bceb5ac;
    classtype:command-and-control;
    sid:2026756; rev:4;
    metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2018_12_07, deployment Perimeter, malware_family Ursa_Loader, performance_impact Moderate, confidence Medium, signature_severity Major, updated_at 2020_09_16;
)

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