ET MALWARE 44Calibar Variant Exfil via Telegram

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"ET MALWARE 44Calibar Variant Exfil via Telegram";
    flow:established,to_server;
    http.request_line;
    content:"POST /bot"; startswith;
    content:"/sendDocument"; distance:0;
    http.host; bsize:16;
    content:"api.telegram.org";
    http.request_body;
    content:"name|3d|caption|0d 0a 0d 0a|";
    content:"44CALIBER"; nocase; within:15; fast_pattern;
    content:"Grabbed Software|3a|"; distance:0;
    reference:md5,fc489c5343f6db7d1be798a3ee331bdf;
    classtype:command-and-control;
    sid:2033455; rev:1;
    metadata:attack_target Client_Endpoint, created_at 2021_07_27, deployment Perimeter, deployment SSLDecrypt, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2021_07_27;
)