Security Testing

Introduction

Purpose: To ensure that the O-RAN system—including all disaggregated components, interfaces, and management layers—maintains confidentiality, integrity, and availability against cyber threats. Security testing validates that every network element (O-DU, O-RU, SMO, Near-RT RIC, O-Cloud, and supporting infrastructure) adheres to O-RAN Alliance security specifications and industry-standard security practices.

Objective: To comprehensively assess whether all O-RAN components, including Open Fronthaul (O-FH), comply with security requirements such as authentication, authorization, encryption, secure transport, and access control. Testing verifies that interfaces are resilient to attacks, securely configured, and enforce proper security controls.

Scope: Security testing covers the entire O-RAN deployment, focusing on:

  • Authentication mechanisms (e.g., SSH, TLS)

  • Secure management interfaces (NETCONF, O1 interface)

  • Encryption and secure transport (DTLS, IPSec)

  • Integrity protection of O-FH (eCPRI) traffic

  • Access control on O-DU/O-RU nodes

  • Vulnerability scanning and configuration checks

  • Interoperability of security configurations in a multi-vendor setup

While this phase emphasizes O-FH, security tests extend to interworking elements, ensuring that threats are mitigated across all layers of the disaggregated architecture.

Security Considerations for Open Fronthaul (O-FH)

The Open Fronthaul interface (between O-DU and O-RU) is critical, as it carries real-time and near-real-time control/user plane traffic. Security testing for O-FH ensures:

Key Requirements:

  • Secure Management Plane Configuration: Ensure that SSH/NETCONF access to O-RU and O-DU is authenticated, encrypted, and restricted.

  • Transport Security: Validate the use of MACsec/IPsec/DTLS where required for protecting non-real-time traffic.

  • Access Control and Hardening: Verify that only authorized hosts can access O-RU/O-DU management ports.

  • Protection Against Attack Vectors: Brute-force login attempts, unauthorized configuration access, tampering with fronthaul synchronization messages, replay/injection attacks.

  • Compliance with O-RAN Security Specifications: O-RAN.WG11.

Applicable Security Test Cases

OTIC security testing aligns with test plans defined by O-RAN Alliance Security WG11 and Test & Integration Focus Group (TIFG). The focus includes:

  • Authentication validation

  • Credential and key management

  • Hardening of management interfaces (SSH, NETCONF, WebUI)

  • Secure Boot and integrity protection

  • Logging, monitoring, and audit verification

  • Vulnerability scanning and configuration assessment

Network Security Protocol - SSH

Objective Verify that the DUT (O-RU or O-DU) only supports SSH algorithms that comply with the O-RAN Security Configuration Guidelines (SCG). This validates SSH Key Exchange (KEX), Host Key, Encryption (Ciphers), and MAC algorithm sets during SSH handshake negotiation.

Goal: - Allowed algorithms are supported - Not allowed algorithms are absent - Optional algorithms behave correctly

Applicability: O-RU / O-DU management plane access; O-FH security compliance; OTIC Security Testing; O-RAN WG11 compliance validation.

Test Environment Setup

The following diagram illustrates a typical setup used for verifying SSH server/client authentication on the O-RAN M-Plane:

Example SSH Security (Server/Client) test setup for O-RAN M-Plane

In this scenario, the DUT (O-RU/O-DU acting as SSH server or client) is isolated within a secure VLAN and integrated with the Security Test Controller at the OTIC. The setup allows validation of SSH handshake, authentication (password/cert), and negotiation of cryptographic algorithms.

  • When testing the SSH Server (e.g., O-RU): The Test Controller acts as the SSH Client (simulating O-DU/SMO) to initiate connections, attempt valid/invalid logins, and verify access controls.

  • When testing the SSH Client (e.g., O-DU): The Test Controller emulates a malicious or standard SSH Server to verify how the DUT handles server host key verification and connection requests.

Pre-Conditions

  • DUT reachable on management interface

  • SSH port enabled

  • List of algorithms (Allowed / Not Allowed / Optional) from O-RAN SCG available

  • SSH client capable of printing negotiated algorithms

Test Procedure

Step 1 — Enumerate Supported SSH Algorithms - Use tools to retrieve negotiated algorithm lists. - Record categories: KEX, Host Key, Ciphers, MAC, Compression.

Step 2 — Compare DUT Algorithms Against O-RAN SCG Tables - Match DUT-advertised algorithms to:

  • Allowed (must appear)

  • Not Allowed (must not appear)

  • Optional (may appear but must be secure)

Expected Results

Pass Criteria - Supports all required allowed algorithms - Rejects all not allowed algorithms - Optional algorithms handled per vendor design - Negotiates secure algorithms during normal SSH login - No indication of weak configurations - Logs negotiation failures if mandated by SCG

Fail Criteria - Any not allowed algorithm is supported - Allowed algorithms are missing - Weak SSH algorithms are present or negotiated

Conclusion

Validating the SSH algorithm suite ensures SSH access to O-RU and O-DU follows O-RAN security guidelines on cryptographic strength. This is essential for securing O-FH management interfaces in a multi-vendor deployment.