alert http $HTTP_SERVERS any -> $EXTERNAL_NET any (msg:"ET WEB_SERVER Generic Webshell Accessed on Internal Server"; flow:established,to_client; file.data; content:"<title> Mailer Created By"; nocase; fast_pattern; content:"type=|22|submit|22 20|name=|22|Enoc|22 20|value=|22|Enviar|22|"; nocase; distance:0; classtype:web-application-attack; sid:2030076; rev:2; metadata:affected_product Web_Server_Applications, attack_target Web_Server, created_at 2020_05_01, deployment Perimeter, confidence Medium, signature_severity Critical, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_05_01;)