ET HUNTING Upload to Links-Server File Sharing Server

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"ET HUNTING Upload to Links-Server File Sharing Server";
    flow:established,to_server;
    urilen:7;
    http.method;
    content:"POST";
    http.uri;
    content:"/upload";
    http.request_body;
    content:"|0d 0a|Content|2d|Disposition|3a 20|form|2d|data|3b 20|name|3d 22|expires|22 0d 0a 0d 0a|";
    pcre:"/^(?:[0-9]{7})/R";
    content:"|0d 0a 2d 2d 2d 2d 2d 2d 2d 2d|"; within:10;
    content:"|0d 0a|Content|2d|Disposition|3a 20|form|2d|data|3b 20|name|3d 22|access_key|22 0d 0a 0d 0a 0d 0a 2d 2d 2d 2d 2d|"; fast_pattern;
    content:"|0d 0a|Content|2d|Disposition|3a 20|form|2d|data|3b 20|name|3d 22|expires|22 0d 0a 0d 0a|"; distance:0;
    pcre:"/^(?:[0-9]{7})/R";
    reference:url,github.com/xtrafrancyz/linx-server;
    classtype:misc-activity;
    sid:2046809; rev:1;
    metadata:attack_target Client_Endpoint, created_at 2023_07_12, deployment Perimeter, deployment SSLDecrypt, performance_impact Moderate, confidence Low, signature_severity Informational, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2023_07_12;
)