ET MALWARE Terse Upload to Free Image Hosting Provider (uploads .im) - Likely Malware

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"ET MALWARE Terse Upload to Free Image Hosting Provider (uploads .im) - Likely Malware";
    flow:established,to_server;
    http.request_line;
    content:"POST /api?upload"; startswith;
    http.host;
    content:"uploads.im"; bsize:10; fast_pattern;
    http.header_names;
    content:!"|0d 0a|User-Agent|0d 0a|";
    content:!"|0d 0a|Referer|0d 0a|";
    reference:md5,897a5b60d609501e0feb06ff8e54d424;
    classtype:command-and-control;
    sid:2031118; rev:1;
    metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2020_10_26, deployment Perimeter, performance_impact Low, confidence Medium, signature_severity Minor, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_10_26;
)