1. Securing VoIP and PSTN from Integrated Signaling Network Vulnerabilities
Hemant Sengar, George Mason University
Ram Dantu, University of North Texas
Duminda Wijesekera, George Mason University

2. Background :

3. Integration of Voice and Data Network? ?

4. Public Switched Telephone Network

5. SS7 Protocol Stack

6. Integrated IP and SS7 Network
Interconnect IP Network to SS7 Network ?

7. SIGTRAN Protocol Suite

8. M2PA in Signaling Transport

9. SS7 Network Security Threats
Telecommunication Deregulation Act,1996 has opened up market
SS7 design and development carried out in different environment from the presently existing one.
Convergence of voice and data networks

10. IP Network Security Threats
Denial of Service (DoS) attacks
Spoofing, Sniffing.
Viruses, Worms etc.
Intrusion

11. Marriage of SS7 and IP Exponential growth of IP Telephony
More ISPs attach to SS7 Network
Threats to Signaling Nodes
May come from SS7 side
or from IP side

12. Signaling Nodes are Exposed
Potential Threats due to Message Content
ISUP’s IAM message populated with Multilevel Precedence and Preemption (MLPP) parameter
Populating CIC of IAM with 0000 value
Caller ID may be spoofed
Contd…

13. Signaling Nodes are Exposed
MGC is used to bridge SIP and ISUP network
Translation of ISUP to SIP and mapping of ISUP parameters into SIP headers
Blind interpretation

14. Signaling Nodes are Exposed
Traffic Flow Analysis
Traffic nature, load, network topology
Subscriber’s behavior and identity
Link Status Messages in IP Network
Processor Outage
Busy
Out of Service

15. Signaling Nodes are Exposed
Misbehaving Node
M2PA based IPSPs have two identifiers
Violation of Protocol State Machine
Continuous Proving
Sequence of exchanged messages

16. Current Status :
IP Network Side
Signaling Nodes may use
SSL
or IPSec

17. Secure Signaling Architecture :?

18. Secure Signaling Architecture :
Trust
Management
Authentication
Gateway
Screening
(Firewall)
Intrusion
Detection
Armor
DoS/Vulnerabilities
Signatures
Rule Changes
Re-Authentication
Trust Negotiation

19. Trust Management: Define Service Level Agreements
Define Access control Policy

20. Authentication: IETF has proposed IPSec for IP Network
Our Proposal of MTPSec for SS7 Network

21. Proposed Solution Security Across MTP3 Layer
Combination of two protocol
Key Exchange (KE) Protocol
Authentication Header (AH) Protocol

22. Authentication Header Format

23. Conclusion
Provides Integrity and Authentication solution to all signaling nodes
Enforces SLA and ACL policy at the interface
Put checks on misbehaving entities

24. Thank You !