dbt allows Binding to an Unrestricted IP Address via socketsocket

Summary

Binding to INADDR_ANY (0.0.0.0) or IN6ADDR_ANY (::) exposes an application on all network interfaces, increasing the risk of unauthorized access.

While doing some static analysis and code inspection, I found the following code binding a socket to INADDR_ANY by passing "" as the address. This effectively binds to any network interface on the local system, not just localhost (127.0.0.1).

Details

As stated in the Python docs, a special form for address is accepted instead of a host address: '' represents INADDR_ANY, equivalent to "0.0.0.0". On systems with IPv6, '' represents IN6ADDR_ANY, which is equivalent to "::".

https://github.com/dbt-labs/dbt-core/blob/main/core/dbt/task/docs/serve.py#L23C38-L23C39

The text around this code also imply the intention is to host docs only on localhost.

PoC

To recreate, run the docs ServeTask.run() to stand up the HTTP server. Then run netstat to see what addresses this process is bound.

Impact

A user who serves docs on an unsecured public network, may unknowingly be hosting an unsecured (http) web site for any remote user/system to access on the same network.

Further references:
https://docs.python.org/3/library/socket.html#socket-families
https://docs.securesauce.dev/rules/PY030
https://cwe.mitre.org/data/definitions/1327.html

Patches

The issue has has been mitigated in dbt-core v1.6.15, dbt-core v1.7.15, and dbt-core v1.8.1 by binding to localhost explicitly by default in dbt docs serve (https://github.com/dbt-labs/dbt-core/issues/10209).