SAPRouter - Port 3299

Basic info

SAP systems are often the crown jewels of enterprise infrastructure. At the heart of many SAP network architectures lies SAPRouter, a critical gateway and proxy tool used to filter and control access to SAP services. In this article, we provide a comprehensive, in-depth guide to penetration testing SAPRouter, exposing attack vectors, enumeration techniques, and post-exploitation methods — all crafted to help cybersecurity professionals assess and exploit this target efficiently.


What Is SAPRouter and Why It Matters in Pentesting

SAPRouter is an application-layer proxy developed by SAP to control traffic between SAP systems, networks, and client applications. It listens by default on TCP port 3299 and acts as a traffic dispatcher with access-control features.

Insecurely configured SAPRouters can allow unauthenticated access to internal SAP services, bypassing traditional firewalls and enabling lateral movement inside the SAP landscape.


Enumerating SAPRouter Services (Port 3299)

TCP 3299

The default port 3299 is SAPRouter’s listening endpoint. During initial reconnaissance, you should:

nmap -sV -p 3299 --script saprouter-enum <target-ip>

Manually connecting to the port using nc or telnet may return valuable banner information:

nc <target-ip> 3299

Look for response patterns like:

M2 7200

This response indicates a running SAPRouter service.


Bypassing Access Control with Route Strings

SAPRouter uses route strings to determine which systems can communicate. A misconfigured or overly permissive saprouttab file can open doors to internal SAP systems.

Structure of a Route String:

/H/<host>/S/<port>

You can chain multiple route segments:

/H/192.168.0.5/S/3299/H/10.10.10.5/S/3200

This allows an external attacker to pivot through the SAPRouter into internal SAP services such as SAP Dispatcher (3200), Gateway (3300), or Message Server (3600).


Exploitation Techniques for SAPRouter

Establishing Route Chains

Misconfigured routers may allow unauthorized clients to create chained connections to restricted internal services.

saprouter -r -H /H/<saprouter-ip>/S/3299/H/<target-sap-ip>/S/3200

Tunneling Arbitrary Traffic

SAPRouter can be abused as a SOCKS-like proxy. With chained route strings, attackers can tunnel various protocols through SAPRouter to reach services like Telnet, RDP, or SAP NetWeaver endpoints.

Command Injection via Weak ACLs

If an attacker can manipulate the saprouttab file (due to misconfigurations or weak file permissions), they can modify routing rules and inject malicious commands or redirect traffic.


⚠️ Common SAPRouter Misconfigurations

Misconfiguration
Impact

No password or access control

Full unauthenticated access to route traffic

Overly permissive saprouttab

Allows chaining to internal services

Exposure of saprouttab via SMB/NFS

Leak of internal route structure

No logging enabled

No traceability of attacker activity


Chaining SAPRouter with Other Exploits

Once access through SAPRouter is achieved, combine it with:

  • SAP RFC abuse (via RFCEXEC)

  • SAP Gateway exploits (such as remote command execution)

  • SAP Management Console vulnerabilities

Route strings can allow pivoting to these services even when not directly exposed externally.


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