ABSTRACT
Law Enforcement Agencies (LEA) around the world utilizes eavesdropping systems that are based on
the Communications Assistance for Law Enforcement Act (CALEA) architecture, which provides a
platform for transmitting and collecting these data for further analysis. Recent security analysis however
has revealed that CALEA is susceptible to Denial-of-Service (DoS) attacks, which could potentially
compromise the ability of the system to transmit, analyse and utilize the captured data in real time. The
primary reason for this is the limited transfer rate allocated for sending data obtained via eavesdropping.
The bandwidth can be easily overwhelmed by dummy messages if the transmission link is hijacked,
resulting in subsequent loss of real data being transmitted. This would be analogous to the SYN flood
attack observed in web servers.
This project proposes a solution to this issue, which involves splitting the original data to be transmitted
into smaller chunks prior to transmission. The motivation is to decrease the probability of packets
containing real data being lost when the bandwidth usage increases when a DOS attack is attempted.
Subsequently larger amount of real data arrives intact at the receiving end, which can then be gainfully
utilized. The process of distinguishing the fake from real messages could be achieved through some
appropriate pattern recognition and classification software, which however would be beyond the scope
of this project. The key activities in this project involve the design, implementation and test of the
performance aspects of the proposed solution to the DOS attack problem.
A brief overview of the CALEA architecture is provided, along with the various key modules that
comprise it. The current solution is proposed after an analysis of various alternatives. The primary
research methodology in this project concerns the design of the experimental tests for the proposed
solution, its implementation, execution, data gathering and subsequent analysis. The trial runs are
repeated for both wireless medium and wired medium in order to compare results. A limited transfer rate
link is used to simulate an overwhelmed link and the FTP protocol is used for the file transfer process. A
performance analysis is shown to indicate the amount of real data that would have been lost without the
use of the solution. A discussion about the strength and weakness of the solution is also provided, along
with avenues for future work.
Table of Contents
Page
ABSTRACT 3
ACKNOWLEDGEMENT 5
PERMISSION SHEET 6
APPROVAL SHEET 7
DECLARATION 8
LIST OF TABLES 9
LIST OF FIGURES 10
LIST OF ABBREVIATIONS/NOTATION/GLOSSARY OF TERMS 11
Chapter
1 INTRODUCTION- - - - - - - - - - - - - - - .12
2 LITRITURE REVIEW- - - - - - - - - - - - - - - 15
2.1 Call Data Channel(CDC) Resource Exhaustion- - - - - - - - - - 15
2.1.1 ISDN Feature Keys- - - - - - - - - - - - ..17
2.1.2 SMS Messaging - - - - - - - - - - - - - - 17
2.1.3 VoIP Signaling- - - - - - - - - - - - - - .18
2.1.4 IP Flow- - - - - - - - - - - - - - .19
2.2 Inbound Attacks- - - - - - - - - - - - - - .19
2.3 Injecting Uncertainty into Packet Traces- - - - - - - - - - - 19
2.3.1 Confusion- - - - - - - - - - - - - - - 19
2.3.2 Subject-Oriented cdma2000 Timestamps - - - - - - - - - - 20
2.3.3 Loss of cdam2000 Direction Information - - - - - - - - - - 20
2.4 In-band Signaling within Service Provider- - - - - - - - - - 20
2.5 Alternatives Methods to Secure the CALEA Architecture - - - - - - - 20
2.5.1 Passive Provisioning with DOW [method 1]- - - - - - - - - 21
2.5.2 CALEA Architecture with middleware Message Queue [method 2]- - - - - - 23
2.6 Chosen Solution: Split Huge File to Minimize Risk- - - - - - - - 24
2.7 Reasons for Chosen Solution over the Other Two Methods Designs- - - - - - 24
3 DESIGN- - - - - - - - - - - - - - - - 27
4 IMPLEMENTATION- - - - - - - - - - - - - - - .30
4.1 AF Simulator Setup- - - - - - - - - - - - - .31
4.2 DF Simulator Setup- - - - - - - - - - - - - .31
4.3 CF Simulator Setup- - - - - - - - - - - - - .32
5 TESTING AND ANALYSIS- - - - - - - - - - - - - - 34
6 CONCLUSION- - - - - - - - - - - - - - - - .41
Reference - - - - - - - - - - - - - - - - .42
Appendix A- - - - - - - - - - - - - - - - - 43
Appendix B - - - - - - - - - - - - - - - - - .48
Appendix C- - - - - - - - - - - - - - - - - 49
