Phishious

Phishious is an open-source ASP.NET Core MVC web application for assessing Secure Email Gateway (SEG) filtering. In its documented workflow, an operator sends benign and then malicious test messages to deliberately nonexistent local-part addresses at target domains, collects the resulting non-delivery reports (NDRs), and analyzes any returned original message headers to infer the gateways and filtering decisions. This is reconnaissance of email-security controls; the workflow does not deliver messages to real users or establish that a phishing message would compromise a victim. The upstream project targets .NET 5.0, which is out of support.