ET MALWARE LeChiffre Ransomware CnC

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"ET MALWARE LeChiffre Ransomware CnC";
    flow:to_server,established;
    http.method;
    content:"GET";
    http.uri;
    content:"/sipvoice.php?"; depth:14; fast_pattern;
    content:"&session="; distance:0;
    http.header;
    content:"Keep-Alive|3a 20|300";
    http.user_agent;
    content:"Mozilla/4.0 (compatible|3b 20|Synapse)"; startswith;
    http.header_names;
    content:!"Accept";
    content:!"Referer|0d 0a|";
    reference:md5,4523ccfd191dcceeae8e884f82f5c7ad;
    reference:url,blog.malwarebytes.org/intelligence/2016/01/draft-lechiffre-a-manually-run-ransomware/;
    classtype:command-and-control;
    sid:2022406; rev:3;
    metadata:attack_target Client_Endpoint, created_at 2016_01_25, deployment Perimeter, signature_severity Major, tag Ransomware, updated_at 2020_06_17, mitre_tactic_id TA0040, mitre_tactic_name Impact, mitre_technique_id T1486, mitre_technique_name Data_Encrypted_for_Impact;
)