FTP session where an empty control-channel command is observed in conjunction with non-printable binary data on the control channel. This pattern reflects malformed or non-FTP-compliant input, commonly seen during TLS handshake attempts on plaintext endpoints, protocol confusion, or automated scanner misfires.

Automated SMTP interaction performing a minimal capability check by issuing EHLO followed by a STARTTLS upgrade request and immediately terminating the session. This pattern is commonly associated with internet-wide scanners, security research crawlers, or opportunistic bots verifying whether an SMTP service supports encrypted communication. The absence of authentication attempts or message submission indicates reconnaissance or service fingerprinting rather than active abuse.

Identifies HTTPS requests targeting the web server root path ("/"), typically used for initial service discovery, host validation, or baseline content inspection prior to deeper enumeration

FTP session where the client issues AUTH TLS to upgrade the connection to Transport Layer Security. This reflects protocol-level encryption negotiation prior to further interaction.

Identifies HTTP GET requests directly targeting the /bad-request path, indicating automated or manual probing of application error-handling routes rather than legitimate navigation flow.