Anomalous outbound SMTP (TCP/25) from NetScaler appliance address space
This rule detects anomalous outbound SMTP (port 25) traffic originating from a NetScaler ADC or Gateway appliance. Since these appliances have no legitimate business requirement to initiate outbound SMTP communication, such traffic is a strong indicator of post-compromise activity, potentially used for command and control or data exfiltration.
Suricata
