ET MALWARE Webshell Execute Command Inbound - Possibly Iran-based M1

alert http any any -> [$HOME_NET,$HTTP_SERVERS] any (
    msg:"ET MALWARE Webshell Execute Command Inbound - Possibly Iran-based M1";
    flow:established,to_server;
    http.method;
    content:"POST";
    http.request_body;
    content:"__VIEWSTATE="; startswith;
    content:"&txtAuthKey=20TyG6eQqEopbFMB&txtCommand="; fast_pattern;
    classtype:command-and-control;
    sid:2033419; rev:1;
    metadata:attack_target Server, created_at 2021_07_25, deployment Perimeter, confidence High, signature_severity Major, tag WebShell, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2021_07_25, mitre_tactic_id TA0003, mitre_tactic_name Persistence, mitre_technique_id T1505, mitre_technique_name Server_Software_Component;
)