Detecting and Mitigating Denial-of-Service Attacks on Voice over IP Networks

Voice over IP (VoIP) is more susceptible to Denial of Service attacks than traditional data traffic, due to the former's low tolerance to delay and jitter. We describe the design of our VoIP Vulnerability Assessment Tool (VVAT) with which we demonstrate vulnerabilities to DoS attacks inherent in many of the popular VoIP applications available today. In our threat model we assume an adversary who is not a network administrator, nor has direct control of the channel and key VoIP elements. His aim is to degrade his victim's QoS without giving away his presence by making his attack look like a normal network degradation. Even black-boxed, applications like Skype that use proprietary protocols show poor performance under specially crafted DoS attacks to its media stream. Finally we show how securing Skype relays not only preserves many of its useful features such as seamless traversal of firewalls but also protects its users from DoS attacks such as recording of conversations and disruption of voice quality. We also present our experiences using virtualization to protect VoIP applications from 'insider attacks'. Our contribution is two fold we: 1) Outline a threat model for VoIP, incorporating our attack models in an open-source network simulator/emulator allowing VoIP vendors to check their software for vulnerabilities in a controlled environment before releasing it. 2) We present two promising approaches for protecting the confidentiality, availability and authentication of VoIP Services

SecMon: End-to-End Quality and Security Monitoring System

The Voice over Internet Protocol (VoIP) is becoming a more available and popular way of communicating for Internet users. This also applies to Peer-to-Peer (P2P) systems and merging these two have already proven to be successful (e.g. Skype). Even the existing standards of VoIP provide an assurance of security and Quality of Service (QoS), however, these features are usually optional and supported by limited number of implementations. As a result, the lack of mandatory and widely applicable QoS and security guaranties makes the contemporary VoIP systems vulnerable to attacks and network disturbances. In this paper we are facing these issues and propose the SecMon system, which simultaneously provides a lightweight security mechanism and improves quality parameters of the call. SecMon is intended specially for VoIP service over P2P networks and its main advantage is that it provides authentication, data integrity services, adaptive QoS and (D)DoS attack detection. Moreover, the SecMon approach represents a low-bandwidth consumption solution that is transparent to the users and possesses a self-organizing capability. The above-mentioned features are accomplished mainly by utilizing two information hiding techniques: digital audio watermarking and network steganography. These techniques are used to create covert channels that serve as transport channels for lightweight QoS measurement's results. Furthermore, these metrics are aggregated in a reputation system that enables best route path selection in the P2P network. The reputation system helps also to mitigate (D)DoS attacks, maximize performance and increase transmission efficiency in the network.Comment: Paper was presented at 7th international conference IBIZA 2008: On Computer Science - Research And Applications, Poland, Kazimierz Dolny 31.01-2.02 2008; 14 pages, 5 figure

Denial of Service in Voice Over IP Networks

In this paper we investigate denial of service (DoS) vulnerabilities in Voice over IP (VoIP) systems, focusing on the ITU-T H.323 family of protocols. We provide a simple characterisation of DoS attacks that allows us to readily identify DoS issues in H.323 protocols. We also discuss network layer DoS vulnerabilities that affect VoIP systems. A number of improvements and further research directions are proposed

Developing Best Practices for Securing VoIP Communication for a non-profit Organization

Voice over Internet Protocol (VoIP) is the most widely used service around the world. The proficiency of it utilizing the web has increased awesome ubiquity in the current years. With this notoriety, there is expanding worry about the wellbeing of the system. The robbery or loss of the information being exchanged is great concern. For example, a basic problem for researchers who are developing safeguards for VoIP systems is the level of threats and other issues experienced by the non-profit organizations while implementing VoIP communication. This problem originated when non-profits received pressure from their donors not to implement VoIP communication because it will record important and valuable information of their bank account, including their bank balance, and consequently, exposing them to the public. Other dangers include safeguarding secrecy, respectability, and accessibility of the system, known as CIA. dangers. To battle these dangers, some security conventions and calculations have been produced. For example, the H.235 has been investigated, their calculations updated, and it is currently regarded as the most recent and effective system for security of the VoIP system. Another method for battling issues and concerns, and one that is the most proficient due to bigger budgets than non-profits, is VoIP being utilized in new structures and the IT work force. Fortunately, the expanding interest of VoIP has guaranteed and emphasized the requirement for more research to build up the effective security structures and countermeasures of CIA threats. This investigation examines the methods by which such security issues concerning VoIP can be set out to give an appropriate, secure and effective method for correspondence and data trade. In this postulation, the analyst will profoundly examine the relief of VoIP security issues

Securing VoIP: A Framework to Mitigate or Manage Risks

In Australia, the past few years have seen Voice over IP (VoIP) move from a niche communications medium used by organisations with the appropriate infrastructure and capabilities to a technology that is available to any one with a good broadband connection. Driven by low cost and no cost phone calls, easy to use VoIP clients and increasingly reliable connections, VoIP is replacing the Public Switch Telephone Network (PSTN) in a growing number of households. VoIP adoption appears to be following a similar path to early Internet adoption, namely little awareness by users of the security implications. Lack of concern about security by VoIP users is probably due to the relatively risk free service provided by the PSTN. However, VoIP applications use the Internet as their communications medium and therefore the risk profile is significantly different to the PSTN. This paper reviews the risks for two VoIP implementation models now being increasingly used in Australian homes; the PC softphone and the Analogue Telephony Adaptor (ATA). An overview of each of the VoIP implementation models is given together with a description of the respective technologies and protocols utilised. The VoIP security threats, applicable to the two VoIP implementation models considered, are enumerated and vulnerabilities that could be exploited are considered. Available security mechanisms that address the identified vulnerabilities are discussed. A practical and pragmatic VoIP security framework is proposed that will enable a user to mitigate or manage the risks associated with using the VoIP implementation models considered. By applying the VoIP security framework a user will be able to deploy a secure VoIP solution appropriate for residential use