alert http $EXTERNAL_NET any -> $HOME_NET any (
msg:"ET WEB_CLIENT Generic Mailer Accessed on External Compromised Server";
flow:established,to_client;
file.data;
content:"<title>Mailer";
content:"<h1>Simple Mailer</h1>"; distance:0; fast_pattern;
content:"for=|22|Emails|22|>Emails|20 3a|</label>"; distance:0;
classtype:web-application-attack;
sid:2031078; rev:2;
metadata:affected_product Web_Server_Applications, attack_target Web_Server, created_at 2020_10_22, deployment Perimeter, confidence Medium, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_10_22;
)