4G/LTE
5G
Security
Telecom

Diameter Protocol Security Attacks

Exploring vulnerabilities and attack vectors in the Diameter protocol within 4G/LTE and 5G networks

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Diameter Security Expert - RFS Cybersecurity Professional in Security Operations Center

Diameter Protocol Security

The authentication and authorization backbone of 4G/LTE networks, replacing SS7 in modern telecommunications infrastructure.

DIAMETER SECURITY BY RFS

Professional Diameter Security Assessment

RFS provides comprehensive Diameter protocol security assessments for 4G/LTE and 5G networks. Our expertise covers authentication vulnerabilities, AVP manipulation attacks, routing security, and implementation flaws across all Diameter interfaces.

S6a Interface Security Analysis
Gx/Rx Policy Control Assessment
Diameter Routing Agent Security
EPC Core Network Protection
Diameter Security Operations Center - Professional Network Security Analysis

Advanced Diameter Protocol Security Analysis

Real-time monitoring and threat detection for 4G/5G networks

Diameter Security Overview
Understanding the Diameter protocol attack surface

Key Vulnerabilities

  • S6a Interface Information Disclosure
  • Diameter Command Injection
  • Diameter Routing Manipulation
  • Identity Spoofing Attacks

Attack Surface

S6a
Multiple - S6a, Gx, Rx, etc.
All Diameter interfaces
Multiple interfaces

Diameter Protocol Fundamentals

Protocol Architecture

Diameter is a peer-to-peer protocol that provides AAA (Authentication, Authorization, and Accounting) services in 4G/LTE and 5G networks. It replaced RADIUS and SS7 protocols in modern telecom networks.

Key Interfaces

Critical interfaces include S6a (MME-HSS), Gx (PCEF-PCRF), Rx (AF-PCRF), S13 (MME-EIR), and S9 (home PCRF-visited PCRF) for roaming scenarios.

Security Features

Diameter includes TLS/IPsec support, peer authentication, and hop-by-hop security, but implementation weaknesses often undermine these security features.

Attack Categories

Authentication Vulnerabilities

Authentication attacks target the Diameter authentication mechanisms to bypass security controls, impersonate legitimate subscribers, or compromise network elements. These attacks often exploit weaknesses in the implementation of authentication protocols or the handling of authentication vectors.

Identity Spoofing Attacks
Impersonates legitimate Diameter nodes to gain unauthorized access or perform malicious actions.
Impact: Unauthorized access, data theft, or service manipulation through trusted identity abuse
Affected Systems: Multiple interfaces

Technical Details

Diameter Protocol Structure
Understanding the technical aspects of Diameter messages and commands

Message Format

0                   1                   2                   3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|    Version    |                 Message Length                |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Command Flags |                  Command Code                 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                         Application-ID                        |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                      Hop-by-Hop Identifier                    |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                      End-to-End Identifier                    |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|  AVPs ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-

Diameter messages consist of a header followed by a variable number of Attribute-Value Pairs (AVPs). The header includes version, message length, command flags, command code, application ID, and identifiers.

Common Commands

  • Authentication-Information-Request/Answer (AIR/AIA)

    Used to retrieve authentication vectors from HSS

  • Update-Location-Request/Answer (ULR/ULA)

    Used to update subscriber location information

  • Credit-Control-Request/Answer (CCR/CCA)

    Used for online charging and policy control

  • Diameter-EAP-Request/Answer (DER/DEA)

    Used for EAP authentication in IMS/VoLTE

Attack Techniques
Common techniques used to exploit Diameter vulnerabilities

Message Manipulation

Attackers can manipulate Diameter messages by:

  • Modifying AVP values to alter subscriber data or service parameters
  • Injecting malicious AVPs to trigger unexpected behavior
  • Removing security-related AVPs to bypass security controls
  • Replaying legitimate messages to trigger unauthorized actions

Protocol Exploitation

Protocol-level exploitation techniques include:

  • Exploiting routing mechanisms to redirect traffic
  • Abusing realm-based routing to impersonate legitimate nodes
  • Leveraging protocol state machine flaws to trigger unexpected behavior
  • Exploiting peer discovery mechanisms to introduce rogue nodes

Protection Strategies

Network Segmentation
Isolate Diameter signaling traffic from untrusted networks
  • Implement dedicated signaling networks for Diameter traffic
  • Use VPNs or private APNs for signaling traffic
  • Apply strict access control at network boundaries
  • Implement proper firewall rules for Diameter ports and interfaces
Diameter Edge Protection
Secure interconnection points with other networks
  • Deploy Diameter Edge Agents (DEAs) at network boundaries
  • Implement topology hiding to protect internal network structure
  • Apply message filtering and validation at edge nodes
  • Implement rate limiting to prevent DoS attacks
Protocol Security
Enhance Diameter protocol security mechanisms
  • Enable TLS/IPsec for Diameter connections
  • Implement strong peer authentication mechanisms
  • Validate message integrity and origin
  • Apply strict AVP validation and filtering

Resources & Tools

Diameter Testing Tools
Security testing tools for Diameter

Specialized tools for testing Diameter protocol security, including protocol analyzers, fuzzing tools, and security scanners.

PyDiameter
Diameter Fuzzer
EPC Test Suite
Technical Documentation
Standards and specifications

Official documentation, standards, and specifications for the Diameter protocol and its security mechanisms.

RFC 6733
3GPP TS 29.272
GSMA IR.88
Code Samples
Example code for testing

Code samples and examples for testing Diameter protocol security, including proof-of-concept exploits and testing scripts.

Python
Java
C/C++

Next Steps

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