TCP 9003
Synopsis
- Xdebug 3 (PHP’s remote debugger) uses TCP port 9003 by default for its DBGp protocol; IDEs like JetBrains PhpStorm, Visual Studio Code (PHP Debug), and NetBeans typically listen on 9003 to receive debug connections from PHP/Xdebug.
- Real-world example: modern PHP development setups (including many Docker-based images) configure Xdebug 3 to connect to host.docker.internal:9003 so the IDE can handle breakpoints and variable inspection.
- Security note: Xdebug exposed or enabled on production servers has been exploited—attackers can trigger Xdebug to connect back to a listener on 9003 and use DBGp commands (including eval) to execute PHP code or exfiltrate data.
- Prior versions (Xdebug 2) commonly used port 9000; Xdebug 3’s default moved to 9003.
Observed activity
Last 30 days
Detailed chart