alert http $EXTERNAL_NET any -> any any (msg:"ET WEB_SERVER Possible AntSword Webshell Commands Inbound"; flow:established,to_server; http.method; content:"POST"; http.request_body; content:"Response.Write(|25|22"; within:50; nocase; content:"eval(System.Text.Encoding.GetEncoding(|25|22"; nocase; distance:0; content:"|25|22).GetString(System.Convert.FromBase64String(|25|22"; nocase; distance:0; content:")|25|3BResponse.End()|25|3B&"; nocase; distance:0; fast_pattern; reference:url,github.com/AntSwordProject/antSword; classtype:web-application-attack; sid:2030037; rev:2; metadata:affected_product Web_Server_Applications, attack_target Web_Server, created_at 2020_04_28, deployment Perimeter, confidence Medium, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_04_28;)