ET MALWARE Possible APT Sarhurst/Husar/Hussarini/Hassar CnC GET

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"ET MALWARE Possible APT Sarhurst/Husar/Hussarini/Hassar CnC GET";
    flow:to_server,established;
    urilen:>40;
    http.method;
    content:"GET";
    http.uri;
    content:"/?"; depth:2;
    content:"AAAAAAAAAA"; distance:0;
    pcre:"/^\/\?(?:[A-Za-z0-9+/]{4})*(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=|[A-Za-z0-9+/]{4})$/";
    http.header;
    content:"Accept|3a 20|Accept|3a|*/*|0d 0a|"; depth:20; fast_pattern;
    http.user_agent;
    content:"Mozilla/4.0 (compatible|3b 20|MSIE 5.5|3b 20|Windows NT 5.0)"; depth:50; endswith;
    reference:url,www.fortinet.com/blog/threat-research/hussarini---targeted-cyber-attack-in-the-philippines.html;
    classtype:targeted-activity;
    sid:2027710; rev:3;
    metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2019_07_15, deployment Perimeter, confidence Medium, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_09_17;
)