GTP Information Disclosure Attacks
Extracting sensitive subscriber and network information from GTP traffic through error message analysis, header inspection, and protocol probing techniques
GTP information disclosure vulnerabilities allow attackers to extract sensitive information about subscribers, network topology, and operational parameters by analyzing GTP-C error messages, headers, and protocol responses. These attacks exploit verbose error handling and insufficient data sanitization in GTP implementations.
Attack Vector
Network-based passive and active reconnaissance
Complexity
Medium - Requires GTP protocol knowledge
Authentication
None required for basic reconnaissance
Extractable Information Types
- • IMSI (International Mobile Subscriber Identity)
- • MSISDN (Mobile phone numbers)
- • IMEI (Device identifiers)
- • GUTI/TMSI (Temporary identifiers)
- • APN (Access Point Names)
- • Cell tower identifiers (CGI/ECGI)
- • Tracking Area Codes (TAC)
- • Routing Area Identifiers (RAI)
- • Geographic location approximation
- • Movement patterns and tracking
- • GGSN/PGW IP addresses
- • SGSN/SGW identifiers
- • Network element versions
- • Roaming partner information
- • Network architecture details
1. Error Message Analysis
Triggering verbose error responses to extract sensitive information from GTP-C error messages.
Technique:
- • Send malformed GTP-C messages to trigger error responses
- • Analyze error codes and cause values for information leakage
- • Extract IMSI, MSISDN, and network identifiers from error messages
- • Map network topology through error response patterns
2. GTP-C Header Inspection
Passive analysis of GTP-C headers to extract subscriber and session information.
Extractable Data:
- • TEID (Tunnel Endpoint Identifier) patterns
- • Sequence numbers revealing session activity
- • Message types indicating subscriber actions
- • Timing analysis for behavior profiling
3. Subscriber Identifier Probing
Active probing techniques to enumerate and validate subscriber identifiers.
Methods:
- • IMSI enumeration through crafted GTP-C queries
- • Validation of subscriber presence in network
- • Correlation of IMSI with MSISDN
- • Device fingerprinting through IMEI extraction
4. Location Tracking
Extracting and correlating location information from GTP messages.
Capabilities:
- • Real-time subscriber location tracking
- • Historical movement pattern analysis
- • Cell tower mapping and triangulation
- • Roaming status and partner network identification
Confidentiality Impact: HIGH
Exposure of sensitive subscriber data, location information, and network topology enables targeted attacks and privacy violations.
Integrity Impact: LOW
Information disclosure itself doesn't modify data, but extracted information can be used for subsequent attacks.
Availability Impact: LOW
Passive reconnaissance has minimal impact on service availability, though active probing may cause minor disruptions.
- •Privacy Violations: Unauthorized tracking and profiling of subscribers
- •Targeted Attacks: Information used for social engineering and phishing
- •Surveillance: State-level or criminal surveillance capabilities
- •Network Reconnaissance: Mapping for advanced persistent threats
- •Regulatory Violations: GDPR and privacy law breaches
Technical Controls
- • Implement minimal error responses without sensitive data
- • Filter and sanitize all GTP-C error messages
- • Deploy GTP firewalls with message inspection
- • Encrypt GTP-C control plane traffic (IPsec)
- • Implement header obfuscation techniques
- • Use TEID randomization to prevent correlation
- • Apply rate limiting for GTP-C queries
- • Enable anomaly detection for probing attempts
Operational Controls
- • Regular security audits of GTP implementations
- • Monitor for information disclosure attempts
- • Implement network segmentation and access controls
- • Apply vendor security patches promptly
- • Conduct penetration testing for information leakage
- • Implement logging and alerting for suspicious queries
- • Train staff on privacy protection requirements
- • Establish incident response procedures
GTPv0
2G GPRS networks - Legacy implementations with minimal security
GTPv1
3G UMTS networks - Widely deployed with known disclosure issues
GTPv2
4G/5G networks - Improved but still susceptible to disclosure