doc: inspector security warning for changing host

Refs: #23444
Refs: #21774

PR-URL: #23640
Reviewed-By: Anna Henningsen <[email protected]>
Reviewed-By: Gireesh Punathil <[email protected]>
Reviewed-By: Colin Ihrig <[email protected]>
Reviewed-By: Sam Roberts <[email protected]>
Reviewed-By: Sakthipriyan Vairamani <[email protected]>
Reviewed-By: Eugene Ostroukhov <[email protected]>

doc/api/cli.md

@@ -144,6 +144,9 @@ Useful when activating the inspector by sending the `SIGUSR1` signal.
 
 Default host is `127.0.0.1`.
 
+See the [security warning](#inspector_security) below regarding the `host`
+parameter usage.
+
 ### `--inspect[=[host:]port]`
 <!-- YAML
 added: v6.3.0
@@ -155,6 +158,22 @@ V8 inspector integration allows tools such as Chrome DevTools and IDEs to debug
 and profile Node.js instances. The tools attach to Node.js instances via a
 tcp port and communicate using the [Chrome DevTools Protocol][].
 
+<a id="inspector_security"></a>
+#### Warning: binding inspector to a public IP:port combination is insecure
+
+Binding the inspector to a public IP (including `0.0.0.0`) with an open port is
+insecure, as it allows external hosts to connect to the inspector and perform
+a [remote code execution][] attack.
+
+If you specify a host, make sure that at least one of the following is true:
+either the host is not public, or the port is properly firewalled to disallow
+unwanted connections.
+
+**More specifically, `--inspect=0.0.0.0` is insecure if the port (`9229` by
+default) is not firewall-protected.**
+
+See the [debugging security implications][] section for more information.
+
 ### `--loader=file`
 <!-- YAML
 added: v9.0.0
@@ -741,6 +760,8 @@ greater than `4` (its current default value). For more information, see the
 [ScriptCoverage]: https://chromedevtools.github.io/devtools-protocol/tot/Profiler#type-ScriptCoverage
 [V8 JavaScript code coverage]: https://v8project.blogspot.com/2017/12/javascript-code-coverage.html
 [debugger]: debugger.html
+[debugging security implications]: https://nodejs.org/en/docs/guides/debugging-getting-started/#security-implications
 [emit_warning]: process.html#process_process_emitwarning_warning_type_code_ctor
 [experimental ECMAScript Module]: esm.html#esm_loader_hooks
 [libuv threadpool documentation]: http://docs.libuv.org/en/latest/threadpool.html
+[remote code execution]: https://www.owasp.org/index.php/Code_Injection

doc/api/inspector.md

@@ -43,6 +43,9 @@ started.
 If wait is `true`, will block until a client has connected to the inspect port
 and flow control has been passed to the debugger client.
 
+See the [security warning](cli.html#inspector_security) regarding the `host`
+parameter usage.
+
 ## inspector.url()
 
 * Returns: {string|undefined}