Subscriber Data Theft

Overview

SS7 subscriber data theft involves unauthorized access to subscriber information through the exploitation of SS7 protocol vulnerabilities. Attackers can extract sensitive subscriber data including IMSI numbers, location information, and service profiles.

Technical Details

These attacks typically leverage the SendAuthenticationInfo (SAI) and UpdateLocation (UL) operations in the SS7 protocol. By impersonating legitimate network elements, attackers can request subscriber data from the Home Location Register (HLR) or Home Subscriber Server (HSS).

Impact

• Exposure of subscriber identity information (IMSI, MSISDN)
• Compromise of authentication vectors (RAND, SRES, Kc)
• Potential for subsequent identity theft or fraud
• Violation of subscriber privacy and regulatory compliance issues
• Potential for service disruption if subscriber data is modified

Attack Methodology

1. Network Reconnaissance

   Identify target network elements such as HLRs, MSCs, and VLRs through SS7 scanning techniques.

2. GT/PC Spoofing

   Impersonate legitimate network elements by spoofing Global Titles (GT) or Point Codes (PC).

3. SendAuthenticationInfo Request

   Send SAI requests to the target HLR to obtain authentication triplets for specific subscribers.

4. UpdateLocation Request

   Send UL requests to obtain subscriber profile information from the HLR.

5. Data Extraction

   Extract and analyze the received subscriber data for further exploitation.

Required Access

Access to the SS7 network, either through a compromised operator connection, SS7 gateway, or a legitimate interconnection point.

Tools Used

• SS7 protocol analyzers (e.g., Wireshark with SS7 plugins)
• Custom SS7 message generation tools
• SigPloit framework
• SS7 scanning and enumeration tools
• IMSI catchers for local subscriber identification

Detection Methods

• Monitor for unusual SS7 traffic patterns, particularly SAI and UL requests from unexpected sources
• Implement SS7 firewalls to detect and block suspicious requests
• Deploy SS7 IDS/IPS systems with signatures for known attack patterns
• Analyze HLR/HSS logs for unauthorized data access attempts
• Monitor for multiple authentication requests for the same subscriber from different networks

Mitigation Strategies

• Implement SS7 firewalls to filter unauthorized requests
• Deploy category 2 and 3 SS7 security measures as defined in GSMA FS.11 and FS.19
• Implement origin address verification for all SS7 messages
• Restrict SAI responses to contain only necessary authentication information
• Implement SMS Home Routing to protect subscriber privacy
• Deploy diameter signaling protection for networks transitioning to 4G/5G

Related Attack Vectors

• Location Tracking

  Using SS7 to track subscriber locations without their knowledge

• SMS Interception

  Intercepting SMS messages through SS7 vulnerabilities

• Call Interception

  Intercepting voice calls through SS7 vulnerabilities

• Fraud Enablement

  Using stolen subscriber data to enable various fraud schemes

References and Standards

• GSMA FS.11 - SS7 Interconnect Security Monitoring Guidelines

  GSMA guidelines for monitoring and securing SS7 interconnections

• GSMA FS.19 - Diameter Interconnect Security

  GSMA guidelines for securing Diameter interconnections

• ITU-T Q.704 - Signalling network functions and messages

  ITU-T recommendation defining SS7 network functions and messages

• ENISA Signalling Security in Telecom SS7/Diameter/5G

  ENISA report on signalling security across generations of mobile networks