ET MALWARE Possible Raspberry Robin Activity (GET)

alert http $HOME_NET any -> $EXTERNAL_NET 1024: (
    msg:"ET MALWARE Possible Raspberry Robin Activity (GET)";
    flow:established,to_server;
    urilen:>25;
    http.method;
    content:"GET";
    http.uri;
    pcre:"/^\/[A-Za-z0-9]{10,11}\//";
    content:!"|2e|";
    http.header;
    content:"Connection|3a 20|Keep|2d|Alive|0d 0a|Accept|3a 20 2a 2f 2a 0d 0a|User|2d|Agent|3a 20|Windows|20|Installer|0d 0a|Host|3a 20|"; startswith; fast_pattern;
    http.header_names;
    content:"|0d 0a|Connection|0d 0a|Accept|0d 0a|User-Agent|0d 0a|Host|0d 0a 0d 0a|"; bsize:42;
    reference:md5,0bdae8ec9a8fd2a6dd9a39eae00c9834;
    reference:url,redcanary.com/blog/raspberry-robin;
    classtype:trojan-activity;
    sid:2037761; rev:3;
    metadata:attack_target Client_Endpoint, created_at 2022_01_20, deployment Perimeter, confidence Medium, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2022_07_14, reviewed_at 2023_08_25;
)