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Telephone Issues

Featuring 6 Papers as of April 30, 2019

  • Security Considerations for Voice over Wi-Fi (VoWiFi) Systems STI Graduate Student Research
    by Joel Chapman - April 30, 2019 

    As the world pivots from Public Switched Telephony Networks (PSTN) to Voice over Internet Protocol (VoIP)-based telephony architectures, users are employing VoIP-based solutions in more situations. Mobile devices have become a ubiquitous part of a person's identity in the developed world. In the United States in 2017, there were an estimated 224.3 million smartphone users, representing about 68% of the total population. The ability to route telephone call traffic over Wi-Fi networks will continue to expand the coverage area of mobile devices, especially into urban areas where high-density construction has previously caused high signal attenuation. Estimates show that by 2020, Wi-Fi-based calling will make up 53% of mobile IP voice service usage (roughly 9 trillion minutes per year) (Xie, 2018). In contrast to the more traditional VoIP solutions, however, the standards for carrier-based Voice over Wi-Fi (VoWiFi) are often proprietary and have not been well-publicized or vetted. This paper examines the vulnerabilities of VoWiFi calling, assesses what common and less well-known attacks are able to exploit those vulnerabilities, and then proposes technological or procedural security protocols to harden telephony systems against adversary exploitation.


  • Security Analysis: Traditional Telephony and IP Telephony by Alan Klein - March 29, 2003 

    The goal of this paper is to take a step back and analyze the security implications of migrating from a traditional telephony architecture to an IP telephony architecture.


  • Unified Communications Technologies by Jason Kelly - January 29, 2003 

    This paper will cover the basics of unified Communications, what it is, how it works and how it is vulnerable to attack.


  • Often Overlooked: PBX and Voice Security in a Networked World by Chris Herrera - January 12, 2003 

    My goal is to bring you up to speed on some of the common risks and specific attacks/countermeasures associated with voice systems.


  • Eavesdropping an IP Telephony Call by Tom Long - October 4, 2002 

    This paper examines the area of call eavesdropping in detail and outlines how the process of eavesdropping has changed as the PBX technology has evolved; it also suggests that the art of call eavesdropping may be easier than ever before.


  • The GSM Standard (An overview of its security) by Suraj Srinivas - December 20, 2001 

    This paper examines the security issues of the Global Systgem for Mobile Communications (GSM), a mobile phone system used throughout the world.


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STI Graduate Student Research - This paper was created by a SANS Technology Institute student as part of the graduate program curriculum.