ET MALWARE Chafer Win32/TREKX Uploading to CnC

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"ET MALWARE Chafer Win32/TREKX Uploading to CnC";
    flow:established,to_server;
    http.method;
    content:"POST";
    http.uri;
    content:".aspx"; endswith;
    http.request_body;
    content:"Content-Disposition|3a 20|form-data|3b|";
    content:"TREK"; distance:0; fast_pattern;
    pcre:"/^[\x20-\x7e\r\n]{0,13}[^\x20-\x7e\r\n]/Rs";
    http.content_type;
    content:"multipart|2f|form-data|3b|";
    http.content_len;
    byte_test:0,<=,255,0,string,dec;
    http.header_names;
    content:!"Referer";
    reference:url,securityintelligence.com/posts/observations-of-itg07-cyber-operations/;
    classtype:command-and-control;
    sid:2027479; rev:3;
    metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, created_at 2019_06_17, deployment Perimeter, malware_family TREKX, performance_impact Low, confidence High, signature_severity Major, tag Chafer, tag APT39, updated_at 2020_09_17;
)