ET MALWARE Possible UPSTYLE Command Attempt

alert http $EXTERNAL_NET any -> $HOME_NET any (
    msg:"ET MALWARE Possible UPSTYLE Command Attempt";
    flow:established,to_server;
    http.method;
    content:"GET";
    http.uri;
    content:"img|5b|"; fast_pattern;
    pcre:"/img\x5b[a-zA-Z0-9+/=]{10,}\x5d/U";
    content:!"|0d 0a|Referer|0d 0a|";
    reference:url,www.volexity.com/blog/2024/04/12/zero-day-exploitation-of-unauthenticated-remote-code-execution-vulnerability-in-globalprotect-cve-2024-3400/;
    reference:url,unit42.paloaltonetworks.com/cve-2024-3400/;
    classtype:trojan-activity;
    sid:2052026; rev:1;
    metadata:affected_product Palo_Alto_Networks, attack_target Networking_Equipment, tls_state TLSDecrypt, created_at 2024_04_12, cve CVE_2024_3400, deployment Perimeter, deployment SSLDecrypt, malware_family UPSTYLE, performance_impact Moderate, confidence Low, signature_severity Major, updated_at 2024_04_12;
    target:dest_ip;
)