Suricata is a network Intrusion Detection System, Intrusion Prevention System and Network Security Monitoring engine. Prior to 8.0.6, the FTP parser in src/app-layer-ftp.c treats a RETR or STOR command sent before PORT or PASV negotiation as a fatal application-layer error instead of a recoverable protocol event. The fatal state disables FTP application-layer parsing for the remainder of the TCP flow, so later commands can evade parser-dependent rules and logging; IPS mode instead drops the flow. This issue is fixed in version 8.0.6.