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.

FTP session where the client issues AUTH TLS to upgrade the connection to TLS and then terminates the session with QUIT without performing further commands. This reflects minimal interaction limited to encryption negotiation and immediate disconnect, commonly observed in capability testing or automated probing.

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.

Client repeatedly sends GET requests to the /bad-request Docker API endpoint, indicating malformed or incompatible traffic against the Docker daemon. This pattern is typically associated with generic internet scanning or tools attempting HTTP interaction without speaking the proper Docker API protocol.