Internet-Security.com TCP port 8004 details

OpenStack Heat (Orchestration service) listens on TCP port 8004 by default for its native REST API (heat-api) in both DevStack and many production deployments.
SAP NetWeaver Application Server (ICM) maps HTTP to port 80NN; therefore, an SAP instance with number 04 serves HTTP on TCP port 8004 (e.g., an AS ABAP/Java instance “04” uses 8004 for its HTTP interface).
No specific, common hacking/exploitation is uniquely tied to port 8004 beyond general exposure of these services if misconfigured.

TCP 8004