Diameter Protocol Security Attacks
Exploring vulnerabilities and attack vectors in the Diameter protocol within 4G/LTE and 5G networks
Diameter Protocol Security
The authentication and authorization backbone of 4G/LTE networks, replacing SS7 in modern telecommunications infrastructure.
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.
Advanced Diameter Protocol Security Analysis
Real-time monitoring and threat detection for 4G/5G networks
Key Vulnerabilities
- S6a Interface Information Disclosure
- Diameter Command Injection
- Diameter Routing Manipulation
- Identity Spoofing Attacks
Attack Surface
Diameter Protocol Fundamentals
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.
Critical interfaces include S6a (MME-HSS), Gx (PCEF-PCRF), Rx (AF-PCRF), S13 (MME-EIR), and S9 (home PCRF-visited PCRF) for roaming scenarios.
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.
Technical Details
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
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
- 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
- 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
- Enable TLS/IPsec for Diameter connections
- Implement strong peer authentication mechanisms
- Validate message integrity and origin
- Apply strict AVP validation and filtering
Security Best Practice
Resources & Tools
Specialized tools for testing Diameter protocol security, including protocol analyzers, fuzzing tools, and security scanners.
Official documentation, standards, and specifications for the Diameter protocol and its security mechanisms.
Next Steps
Explore our comprehensive methodology for conducting security assessments of Diameter
Discover detailed information about specific Diameter attack vectors, including technical details, impact analysis, and real-world examples of how these vulnerabilities can be exploited.