ET MALWARE Win32/Bisonal RC4 Encrypted 8 Byte Static CnC Checkin

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"ET MALWARE Win32/Bisonal RC4 Encrypted 8 Byte Static CnC Checkin";
    flow:established,to_server;
    urilen:<100;
    http.method;
    content:"POST";
    http.request_body;
    content:"|81 b2 a8 97 7e a3 1b 91|"; depth:8; fast_pattern; endswith;
    http.header_names;
    content:!"Referer";
    content:!"Accept";
    reference:md5,CC71620DE7216B186DA2C9BA06703613;
    reference:url,researchcenter.paloaltonetworks.com/2018/07/unit42-bisonal-malware-used-attacks-russia-south-korea/;
    classtype:command-and-control;
    sid:2025923; rev:3;
    metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2018_07_31, deployment Perimeter, malware_family Bisonal, performance_impact Low, confidence Medium, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_09_16;
)