Critical Infrastructures You Can Trust: Where Telecommunications Fits

This paper discusses two NISs: the public telephone network (PTN) and the Internet. Being themselves large and complex NISs, they not only merit study in their own right but can help us to understand some of the technical problems faced by the developers and operators of other NISs. In addition, the high cost of building a global communications infrastructure from the ground up implies that one or both of these two networks is likely to furnish communications services for most other NISs. Therefore, an understanding of the vulnerabilties of the PTN and Internet informs the assessment of the trustworthiness of other NISs. Ideas for improving the trustworthiness of the PTN and Internet are also proposed, both for the short-term (by improved use of existing technologies and procedures) and for the long-term (by identifying some areas where the state-of-the-art is inadequate and research is therefore needed). Finally, some observations are offered about Internet telephony and the use of the Internet for critical infrastructures

Analysis of GPRS Limitations

The General Packet Radio Service (GPRS) is a new standard for mobile data communications, which is implemented under the existing infrastructure of Global System for Mobile Communications (GSM). The promise capability of handling Internet Protocol traffic enables instant and constant connection to global network regardless of location and time. With its packet-based nature, the new technology facilitates new applications in wireless communications that have not been available previously. Nonetheless, there are numbers of limitations that have to be taken into consideration b~fore this technology can be implemented commercially. Despite all arguments and challenges, the GPRS system is here to stay and evolving towards the third generation mobile communications. This report covers the background of the GPRS and discusses the issues involved in implementing this current technology besides considering the deployment of third generation networks beyond GPRS

Analysis and Mitigation of Recent Attacks on Mobile Communication Backend

2014 aasta viimases kvartalis demonstreeriti mitmeid edukaid rünnakuid mobiilsidevõrkude vastu. Need baseerusid ühe peamise signaaliprotokolli, SS7 väärkasutamisel. Ründajatel õnnestus positsioneerida mobiilseadmete kasutajaid ja kuulata pealt nii kõnesid kui ka tekstisõnumeid. Ajal mil enamik viimase aja ründeid paljastavad nõrkusi lõppkasutajate seadmete tarkvaras, paljastavad need hiljutised rünnakud põhivõrkude endi haavatavust. Teadaolevalt on mobiilsete telekommunikatsioonivõrkude tööstuses raskusi haavatavuste õigeaegsel avastamisel ja nende mõistmisel. Käesolev töö on osa püüdlusest neid probleeme mõista. Töö annab põhjaliku ülevaate ja analüüsib teadaolevaid rünnakuid ning toob välja võimalikud lahendused. Rünnakud võivad olla väga suurte tagajärgedega, kuna vaatamata SS7 protokolli vanusele, jääb see siiski peamiseks signaaliprotokolliks mobiilsidevõrkudes veel pikaks ajaks. Uurimustöö analüüs ja tulemused aitavad mobiilsideoperaatoritel hinnata oma võrkude haavatavust ning teha paremaid investeeringuid oma taristu turvalisusele. Tulemused esitletakse mobiilsideoperaatoritele, võrguseadmete müüjatele ning 3GPP standardi organisatsioonile.In the last quarter of 2014, several successful attacks against mobile networks were demonstrated. They are based on misuse of one of the key signaling protocol, SS7, which is extensively used in the mobile communication backend for signaling tasks such as call and mobility management. The attackers were able to locate the mobile users and intercept voice calls and text messages. While most attacks in the public eye are those which exploits weaknesses in the end-device software or radio access links, these recently demonstrated vulnerabilities exploit weaknesses of the mobile core networks themselves. Understandably, there is a scramble in the mobile telecommunications industry to understand the attacks and the underlying vulnerabilities. This thesis is part of that effort. This thesis presents a broad and thorough overview and analysis of the known attacks against mobile network signaling protocols and the possible mitigation strategies. The attacks are presented in a uniform way, in relation to the mobile network protocol standards and signaling scenarios. Moreover, this thesis also presents a new attack that enables a malicious party with access to the signaling network to remove lost or stolen phones from the blacklist that is intended to prevent their use. Both the known and new attacks have been confirmed by implementing them in a controlled test environment. The attacks are serious because SS7, despite its age, remains the main signaling protocol in the mobile networks and will still long be required for interoperability and background compatibility in international roaming. Moreover, the number of entities with access to the core network, and hence the number of potential attackers, has increased significantly because of changes in regulation and opening of the networks to competition. The analysis and new results of this thesis will help mobile network providers and operators to assess the vulnerabilities in their infrastructure and to make security-aware decisions regarding their future investments and standardization. The results will be presented to the operators, network-equipment vendors, and to the 3GPP standards body

A Logically Centralized Approach for Control and Management of Large Computer Networks

Management of large enterprise and Internet Service Provider networks is a complex, error-prone, and costly challenge. It is widely accepted that the key contributors to this complexity are the bundling of control and data forwarding in traditional routers and the use of fully distributed protocols for network control. To address these limitations, the networking research community has been pursuing the vision of simplifying the functional role of a router to its primary task of packet forwarding. This enables centralizing network control at a decision plane where network-wide state can be maintained, and network control can be centrally and consistently enforced. However, scalability and fault-tolerance concerns with physical centralization motivate the need for a more flexible and customizable approach. This dissertation is an attempt at bridging the gap between the extremes of distribution and centralization of network control. We present a logically centralized approach for the design of network decision plane that can be realized by using a set of physically distributed controllers in a network. This approach is aimed at giving network designers the ability to customize the level of control and management centralization according to the scalability, fault-tolerance, and responsiveness requirements of their networks. Our thesis is that logical centralization provides a robust, reliable, and efficient paradigm for management of large networks and we present several contributions to prove this thesis. For network planning, we describe techniques for optimizing the placement of network controllers and provide guidance on the physical design of logically centralized networks. For network operation, algorithms for maintaining dynamic associations between the decision plane and network devices are presented, along with a protocol that allows a set of network controllers to coordinate their decisions, and present a unified interface to the managed network devices. Furthermore, we study the trade-offs in decision plane application design and provide guidance on application state and logic distribution. Finally, we present results of extensive numerical and simulative analysis of the feasibility and performance of our approach. The results show that logical centralization can provide better scalability and fault-tolerance while maintaining performance similarity with traditional distributed approach

Analysis and Mitigation of Recent Attacks on Mobile Communication Backend

In the last quarter of 2014, several successful attacks against mobile networks were demonstrated. They are based on misuse of one of the key signaling protocol, SS7, which is extensively used in the mobile communication backend for signaling tasks such as call and mobility management. The attackers were able to locate the mobile users and intercept voice calls and text messages. While most attacks in the public eye are those which exploits weaknesses in the end-device software or radio access links, these recently demonstrated vulnerabilities exploit weaknesses of the mobile core networks themselves. Understandably, there is a scramble in the mobile telecommunications industry to understand the attacks and the underlying vulnerabilities. This thesis is part of that effort. This thesis presents a broad and thorough overview and analysis of the known attacks against mobile network signaling protocols and the possible mitigation strategies. The attacks are presented in a uniform way, in relation to the mobile network protocol standards and signaling scenarios. Moreover, this thesis also presents a new attack that enables a malicious party with access to the signaling network to remove lost or stolen phones from the blacklist that is intended to prevent their use. Both the known and new attacks have been confirmed by implementing them in a controlled test environment. The attacks are serious because SS7, despite its age, remains the main signaling protocol in the mobile networks and will still long be required for interoperability and background compatibility in international roaming. Moreover, the number of entities with access to the core network, and hence the number of potential attackers, has increased significantly because of changes in regulation and opening of the networks to competition. The analysis and new results of this thesis will help mobile network providers and operators to assess the vulnerabilities in their infrastructure and to make security-aware decisions regarding their future investments and standardization. The results will be presented to the operators, network-equipment vendors, and to the 3GPP standards body

Voice over IP

The area that this thesis covers is Voice over IP (or IP Telephony as it is sometimes called) over Private networks and not over the Internet. There is a distinction to be made between the two even though the term is loosely applied to both. IP Telephony over Private Networks involve calls made over private WANs using IP telephony protocols while IP Telephony over the Internet involve calls made over the public Internet using IP telephony protocols. Since the network is private, service is reliable because the network owner can control how resources are allocated to various applications, such as telephony services. The public Internet on the other hand is a public, largely unmanaged network that offers no reliable service guarantee. Calls placed over the Internet can be low in quality, but given the low price, some find this solution attractive. What started off as an Internet Revolution with free phone calls being offered to the general public using their multimedia computers has turned into a telecommunication revolution where enterprises are beginning to converge their data and voice networks into one network. In retrospect, an enterprise\u27s data networks are being leveraged for telephony. The communication industry has come full circle. Earlier in the decade data was being transmitted over the public voice networks and now voice is just another application which is/will be run over the enterprises existing data networks. We shall see in this thesis the problems that are encountered while sending Voice over Data networks using the underlying IP Protocol and the corrective steps taken by the Industry to resolve these multitudes of issues. Paul M. Zam who is collaborating in this Joint Thesis/project on VoIP will substantiate this theoretical research with his practical findings. On reading this paper the reader will gain an insight in the issues revolving the implementation of VoIP in an enterprises private network as well the technical data, which sheds more light on the same. Thus the premise of this joint thesis/project is to analyze the current status of the technology and present a business case scenario where an organization will be able to use this information