Diameter Command Injection

Critical Risk

4G/5G Networks

Diameter Protocol

Attack Vector Overview

Diameter Command Injection attacks manipulate Diameter protocol messages to inject malicious commands that can compromise network elements, modify subscriber data, or disrupt services in 4G/5G networks.

Technical Details

How Diameter Command Injection attacks work

Diameter Command Injection attacks exploit vulnerabilities in the Diameter protocol implementation to inject malicious commands or manipulate Attribute-Value Pairs (AVPs) in legitimate Diameter messages. These attacks can target various Diameter interfaces in 4G/5G networks, including S6a, S6d, S13, and Cx.

Attack Methodology

Network Reconnaissance: Attackers identify Diameter nodes and interfaces in the target network.
Message Interception or Crafting: Attackers either intercept legitimate Diameter messages or craft malicious ones from scratch.
Command Injection: Malicious AVPs or commands are injected into Diameter messages.
Message Delivery: The modified or crafted messages are sent to target Diameter nodes.
Exploitation: The receiving node processes the injected commands, leading to unauthorized actions or system compromise.

Figure 1: Diameter Command Injection Attack Flow

Vulnerable Interfaces and Commands

Interface	Command	Injection Target	Potential Impact
S6a (MME-HSS)	Update-Location-Request (ULR)	Subscriber-Status AVP	Unauthorized service activation/deactivation
S6a (MME-HSS)	Authentication-Information-Request (AIR)	Requested-EUTRAN-Authentication-Info AVP	Authentication vector theft
Gx (PCEF-PCRF)	Credit-Control-Request (CCR)	Charging-Rule-Install AVP	Unauthorized policy modification
Cx (I/S-CSCF-HSS)	Server-Assignment-Request (SAR)	Server-Assignment-Type AVP	IMS service hijacking

Example Attack Scenario

1. Attacker crafts a malicious Update-Location-Request (ULR) with injected commands:

<diameter version="1.0">
  <header command_code="316" application_id="16777251" flags="request">
    <origin host="compromised-mme.operator.com" realm="operator.com" />
    <destination host="hss.operator.com" realm="operator.com" />
  </header>
  <avp code="1" name="User-Name" value="234150999999999" />
  <avp code="10415:1032" name="RAT-Type" value="1004" />
  <avp code="10415:1407" name="ULR-Flags" value="34" />
  <avp code="10415:1400" name="Subscriber-Status" value="0" />
  <!-- Injected malicious AVP -->
  <avp code="10415:1424" name="Access-Restriction-Data" value="0" />
</diameter>

2. The injected Access-Restriction-Data AVP removes all service restrictions for the subscriber, potentially allowing unauthorized access to premium services.

Impact Assessment

Diameter Command Injection attacks can have severe consequences for mobile network operators and subscribers:

Service Manipulation

Unauthorized service activation or deactivation
Modification of subscriber QoS profiles
Bypassing of service restrictions
Unauthorized access to premium services

Network Disruption

Denial of service for targeted subscribers
Overloading of network elements
Disruption of authentication processes
Interference with charging and billing systems

Security Compromise

Theft of authentication vectors
Subscriber impersonation
Bypass of security controls
Potential for persistent backdoor installation

Financial Impact

Revenue loss from service theft
Billing fraud
Regulatory fines for security breaches
Increased operational costs for incident response

Risk Factors

The risk is particularly high for operators with inadequate Diameter message validation, lack of proper authentication between Diameter nodes, or insufficient monitoring of Diameter signaling traffic.

Detection & Mitigation

Detection Methods

Detecting Diameter Command Injection attacks requires comprehensive monitoring and analysis of Diameter signaling traffic:

Deep Packet Inspection: Analyze Diameter messages to identify malformed or suspicious AVPs.
Behavioral Analysis: Monitor for unusual patterns in Diameter command usage or frequency.
AVP Validation: Check for unexpected or unauthorized AVPs in Diameter messages.
Command Sequence Analysis: Detect abnormal sequences of Diameter commands that deviate from expected protocol flows.
Origin Verification: Verify that Diameter messages originate from authorized and expected sources.

Key Indicators of Compromise

Unexpected AVPs in Diameter messages
Unusual combinations of AVPs or command codes
Diameter messages with inconsistent or contradictory AVPs
High frequency of specific Diameter commands from a single source
Diameter messages with modified mandatory AVPs
Unexpected changes to subscriber profiles or service settings

Related Attack Vectors

Standards & References

3GPP TS 29.272Evolved Packet System (EPS); Mobility Management Entity (MME) and Serving GPRS Support Node (SGSN) related interfaces based on Diameter protocol
RFC 6733Diameter Base Protocol
GSMA FS.19Diameter Interconnection Security
NIST SP 800-187Guide to LTE Security

Tools & Resources

1
Diameter Protocol FuzzerTool for testing Diameter implementations against malformed messages
2
Diameter Security ScannerSpecialized tool for identifying vulnerabilities in Diameter implementations
3
Wireshark with Diameter DissectorNetwork protocol analyzer with Diameter protocol support