SS7 Security Expert - RFS Cybersecurity Professional in Futuristic Network Environment
SS7 Security Expert

SS7 Stack Securityby RFS

Advanced SS7 vulnerability assessment, attack vector analysis, and security testing methodologies for telecommunications signaling networks

Signaling Security
Telecommunications
Mobile Networks
Pentesting

Professional SS7 Security Assessment

RFS provides comprehensive SS7 security assessments, vulnerability analysis, and penetration testing services for telecommunications operators and enterprises. Our expertise covers the full spectrum of SS7 attack vectors and defensive strategies.

Location Tracking Attack Assessment
SMS/Call Interception Testing
SS7 Firewall Configuration Review
Signaling Network Security Architecture
SS7 Security Professional - Expert Telecommunications Security Assessment

SS7 Security by RFS

Advanced Signaling Security Expert

SS7 Protocol Security Overview

The Signaling System No. 7 (SS7) protocol suite is the backbone of global telecommunications, enabling mobile roaming, call setup, SMS delivery, and billing operations across operator networks worldwide. Originally designed in the 1970s with a focus on reliability rather than security, SS7 now faces significant security challenges in today's interconnected world.

Critical Security Impact

SS7 vulnerabilities can lead to location tracking, call and SMS interception, service disruption, and fraud. These attacks can be executed remotely with minimal resources by attackers with SS7 network access.

Key Vulnerability Factors

  • Implicit Trust Model: SS7 was designed with the assumption that all connected networks are trustworthy
  • Lack of Authentication: No strong authentication mechanisms for network elements or messages
  • No Encryption: Signaling messages are transmitted in cleartext across interconnection networks
  • Global Reachability: Any connected network can potentially reach any subscriber worldwide
  • Legacy Integration: Backward compatibility requirements with legacy systems limit security improvements

Learn about network intrusion detection for SS7 networks

Explore cybersecurity incident response procedures

SS7 Network Evolution

Traditional SS7

Circuit-switched networks with physical point codes

SIGTRAN

SS7 over IP networks with enhanced transport

Diameter

Next-generation protocol for 4G/LTE networks

SS7 Security Components
Key components and their security implications

Signaling Transfer Points (STPs)

Network nodes that route SS7 messages between different networks

Vulnerable to unauthorized access and message manipulation

Home Location Register (HLR)

Database containing subscriber information and current location

Target for subscriber data theft and location tracking attacks

Mobile Switching Center (MSC)

Handles call setup, routing, and subscriber mobility

Vulnerable to call interception and service disruption attacks

SS7 Firewall

Security control for filtering malicious SS7 messages

Critical defensive measure for protecting the SS7 network

SS7 Security Architecture

SS7 Security Architecture Diagram

Key Security Controls

SS7 Firewall

Filters malicious SS7 messages based on message type, origin, and content

SMS Home Routing

Prevents direct access to HLR by routing all SMS through the home network

Monitoring Systems

Detect and alert on suspicious SS7 activity in real-time

Common SS7 Attack Vectors

Location Tracking
Techniques to track subscriber location without consent

Key Techniques:

  • SendRoutingInfoForSM Abuse
  • AnyTimeInterrogation Exploitation
  • ProvideSubscriberInfo Attack
Call Interception
Methods to intercept voice calls and conversations

Key Techniques:

  • UpdateLocation Hijacking
  • InsertSubscriberData Manipulation
  • Call Forwarding Exploitation
SMS Interception
Techniques to intercept SMS messages

Key Techniques:

  • SendRoutingInfoForSM Exploitation
  • ForwardSM Manipulation
  • SMSC Spoofing

Real-World Impact of SS7 Vulnerabilities

Banking Fraud

In 2017, attackers exploited SS7 vulnerabilities to intercept SMS-based two-factor authentication codes sent to German bank customers. This allowed them to bypass security measures and drain accounts.

Attack Vector:

SMS interception through SS7 network to capture one-time passwords

Privacy Violations

Law enforcement agencies and private companies have used SS7 vulnerabilities to track individuals' locations without judicial oversight, raising serious privacy concerns.

Attack Vector:

Location tracking through SendRoutingInfoForSM and AnyTimeInterrogation operations

Critical Infrastructure Implications

SS7 vulnerabilities can impact critical infrastructure that relies on mobile networks for operations, including power grids, water systems, and emergency services. Attackers could potentially disrupt service or intercept sensitive communications during emergencies.

SS7 Exploitation Techniques

Subscriber Location Tracking
Exploiting SS7 operations to determine subscriber location
Medium Complexity
High Impact

Attack Description:

This attack exploits the AnyTimeInterrogation (ATI) operation in SS7 to query the HLR for a subscriber's current location. The attack can reveal the target's location down to the cell tower level without their knowledge or consent.

Prerequisites:

  • SS7 network access (direct or via compromised operator)
  • Target's MSISDN (phone number)
  • SS7 message crafting capability

Key Steps:

  1. Craft ATI request with target MSISDN
  2. Send request to target's home network
  3. Receive and parse location information
  4. Convert cell ID to geographic coordinates

SS7 Defensive Strategies

SS7 Firewall

Deploy specialized SS7 firewalls that can filter malicious messages based on origin, message type, and content patterns.

Key Protection:

Blocks unauthorized location tracking, SMS interception, and call forwarding attacks

SMS Home Routing

Implement SMS home routing to ensure all SMS messages are routed through the home network, preventing direct access to the HLR.

Key Protection:

Prevents SMS interception and subscriber data theft via SendRoutingInfoForSM

Monitoring & Detection

Deploy real-time monitoring systems to detect and alert on suspicious SS7 activity patterns indicative of attacks.

Key Protection:

Early detection of attack attempts, enabling rapid response and mitigation

Comprehensive Defense Strategy

Effective SS7 security requires a multi-layered approach combining technical controls, operational procedures, and industry collaboration:

  • Technical Controls: SS7 firewalls, SMS home routing, monitoring systems, and category-based filtering
  • Operational Procedures: Regular security assessments, incident response planning, and staff training
  • Industry Collaboration: Information sharing about threats, adherence to GSMA security guidelines, and participation in security working groups
  • Evolution: Migration to more secure protocols like Diameter with proper security controls and eventual transition to 5G networks

Related Security Resources

Explore related telecommunications security topics and attack methodologies.

5G Security
Security vulnerabilities in 5G networks
5G Security
4G Security
Security vulnerabilities in 4G networks
4G Security
Diameter Attacks
Vulnerabilities in the Diameter protocol
Diameter Attacks