Patterns and Interactions in Network Security

Networks play a central role in cyber-security: networks deliver security attacks, suffer from them, defend against them, and sometimes even cause them. This article is a concise tutorial on the large subject of networks and security, written for all those interested in networking, whether their specialty is security or not. To achieve this goal, we derive our focus and organization from two perspectives. The first perspective is that, although mechanisms for network security are extremely diverse, they are all instances of a few patterns. Consequently, after a pragmatic classification of security attacks, the main sections of the tutorial cover the four patterns for providing network security, of which the familiar three are cryptographic protocols, packet filtering, and dynamic resource allocation. Although cryptographic protocols hide the data contents of packets, they cannot hide packet headers. When users need to hide packet headers from adversaries, which may include the network from which they are receiving service, they must resort to the pattern of compound sessions and overlays. The second perspective comes from the observation that security mechanisms interact in important ways, with each other and with other aspects of networking, so each pattern includes a discussion of its interactions.Comment: 63 pages, 28 figures, 56 reference

Applications of Context-Aware Systems in Enterprise Environments

In bring-your-own-device (BYOD) and corporate-owned, personally enabled (COPE) scenarios, employees’ devices store both enterprise and personal data, and have the ability to remotely access a secure enterprise network. While mobile devices enable users to access such resources in a pervasive manner, it also increases the risk of breaches for sensitive enterprise data as users may access the resources under insecure circumstances. That is, access authorizations may depend on the context in which the resources are accessed. In both scenarios, it is vital that the security of accessible enterprise content is preserved. In this work, we explore the use of contextual information to influence access control decisions within context-aware systems to ensure the security of sensitive enterprise data. We propose several context-aware systems that rely on a system of sensors in order to automatically adapt access to resources based on the security of users’ contexts. We investigate various types of mobile devices with varying embedded sensors, and leverage these technologies to extract contextual information from the environment. As a direct consequence, the technologies utilized determine the types of contextual access control policies that the context-aware systems are able to support and enforce. Specifically, the work proposes the use of devices pervaded in enterprise environments such as smartphones or WiFi access points to authenticate user positional information within indoor environments as well as user identities

SafeExit: Exit Node Protection for TOR

TOR is one of the most important networks for providing anonymity over the internet. However, in some cases its exit node operators open themselves up to various legal challenges, a fact which discourages participation in the network. In this paper, we propose a mechanism for allowing some users to be voluntarily verified by trusted third parties, providing a means by which an exit node can verify that they are not the true source of traffic. This is done by extending TOR’s anonymity model to include another class of user, and using a web of trust mechanism to create chains of trust

Malware-Resistant Protocols for Real-World Systems

Cryptographic protocols are widely used to protect real-world systems from attacks. Paying for goods in a shop, withdrawing money or browsing the Web; all these activities are backed by cryptographic protocols. However, in recent years a potent threat became apparent. Malware is increasingly used in attacks to bypass existing security mechanisms. Many cryptographic protocols that are used in real-world systems today have been found to be susceptible to malware attacks. One reason for this is that most of these protocols were designed with respect to the Dolev-Yao attack model that assumes an attacker to control the network between computer systems but not the systems themselves. Furthermore, most real-world protocols do not provide a formal proof of security and thus lack a precise definition of the security goals the designers tried to achieve. This work tackles the design of cryptographic protocols that are resilient to malware attacks, applicable to real-world systems, and provably secure. In this regard, we investigate three real-world use cases: electronic payment, web authentication, and data aggregation. We analyze the security of existing protocols and confirm results from prior work that most protocols are not resilient to malware. Furthermore, we provide guidelines for the design of malware-resistant protocols and propose such protocols. In addition, we formalize security notions for malware-resistance and use a formal proof of security to verify the security guarantees of our protocols. In this work we show that designing malware-resistant protocols for real-world systems is possible. We present a new security notion for electronic payment and web authentication, called one-out-of-two security, that does not require a single device to be trusted and ensures that a protocol stays secure as long as one of two devices is not compromised. Furthermore, we propose L-Pay, a cryptographic protocol for paying at the point of sale (POS) or withdrawing money at an automated teller machine (ATM) satisfying one-out-of-two security, FIDO2 With Two Displays (FIDO2D) a cryptographic protocol to secure transactions in the Web with one-out-of-two security and Secure Aggregation Grouped by Multiple Attributes (SAGMA), a cryptographic protocol for secure data aggregation in encrypted databases. In this work, we take important steps towards the use of malware-resistant protocols in real-world systems. Our guidelines and protocols can serve as templates to design new cryptographic protocols and improve security in further use cases

IoT Protocols And Security

During the past years, there has been an exponential growth of internet connected devices all over the world. In future the growth of these devices is expected to grow at the higher rate. There are some studies estimating that Internet of Things (IoT) will be able to connects 500 billion devices by 2030. IoT smart devices are remotely accessible and are possible to control using existing network infrastructure. At present, the usage of Internet of Things has increased rapidly. IoT is a dynamic global network between smart objects or things connected over the internet. IoT wireless network can connect anyone with anything at any place. With the rapid growth of IoT, security threats and vulnerabilities of the linked objects are also increasing continuously. Now, IoT security has become the most paramount technological research work over the world. The main objective of all IoT applications is to maintaining privacy and secure data transmission between devices. Due to the heterogeneous characteristics and constrained devices it is challenging to deploy security mechanisms in IoT compare to traditional network. In this thesis, we highlight the importance of security in the IoT sector by studying a wide range of IoT security issues. Furthermore, we described several challenges derived from the existing IoT protocols and the security features of IoT protocols are also explained. In addition, implementation of UDP communication protocol and MQTT protocol using Contiki OS and Zolertia RE-Mote devices are added to the work. Cryptographic methods AES [1] and ECC [2] are described in the thesis and the implementation of AES-128 to secure device communication and ECC key generation process are also added to the thesis work

A security protocol for authentication of binding updates in Mobile IPv6.

Wireless communication technologies have come along way, improving with every generational leap. As communications evolve so do the system architectures, models and paradigms. Improvements have been seen in the jump from 2G to 3G networks in terms of security. Yet these issues persist and will continue to plague mobile communications into the leap towards 4G networks if not addressed. 4G will be based on the transmission of Internet packets only, using an architecture known as mobile IP. This will feature many advantages, however security is still a fundamental issue to be resolved. One particular security issue involves the route optimisation technique, which deals with binding updates. This allows the corresponding node to by-pass the home agent router to communicate directly with the mobile node. There are a variety of security vulnerabilities with binding updates, which include the interception of data packets, which would allow an attacker to eavesdrop on its contents, breaching the users confidentiality, or to modify transmitted packets for the attackers own malicious purposes. Other possible vulnerabilities with mobile IP include address spoofing, redirection and denial of service attacks. For many of these attacks, all the attacker needs to know is the IPv6 addresses of the mobile’s home agent and the corresponding node. There are a variety of security solutions to prevent these attacks from occurring. Two of the main solutions are cryptography and authentication. Cryptography allows the transmitted data to be scrambled in an undecipherable way resulting in any intercepted packets being illegible to the attacker. Only the party possessing the relevant key will be able to decrypt the message. Authentication is the process of verifying the identity of the user or device one is in communication with. Different authentication architectures exist however many of them rely on a central server to verify the users, resulting in a possible single point of attack. Decentralised authentication mechanisms would be more appropriate for the nature of mobile IP and several protocols are discussed. However they all posses’ flaws, whether they be overly resource intensive or give away vital address data, which can be used to mount an attack. As a result location privacy is investigated in a possible attempt at hiding this sensitive data. Finally, a security solution is proposed to address the security vulnerabilities found in binding updates and attempts to overcome the weaknesses of the examined security solutions. The security protocol proposed in this research involves three new security techniques. The first is a combined solution using Cryptographically Generated Addresses and Return Routability, which are already established solutions, and then introduces a new authentication procedure, to create the Distributed Authentication Protocol to aid with privacy, integrity and authentication. The second is an enhancement to Return Routability called Dual Identity Return Routability, which provides location verification authentication for multiple identities on the same device. The third security technique is called Mobile Home Agents, which provides device and user authentication while introducing location privacy and optimised communication routing. All three security techniques can be used together or individually and each needs to be passed before the binding update is accepted. Cryptographically Generated Addresses asserts the users ownership of the IPv6 address by generating the interface identifier by computing a cryptographic one-way hash function from the users’ public key and auxiliary parameters. The binding between the public key and the address can be verified by recomputing the hash value and by comparing the hash with the interface identifier. This method proves ownership of the address, however it does not prove the address is reachable. After establishing address ownership, Return Routability would then send two security tokens to the mobile node, one directly and one via the home agent. The mobile node would then combine them together to create an encryption key called the binding key allowing the binding update to be sent securely to the correspondent node. This technique provides a validation to the mobile nodes’ location and proves its ownership of the home agent. Return Routability provides a test to verify that the node is reachable. It does not verify that the IPv6 address is owned by the user. This method is combined with Cryptographically Generated Addresses to provide best of both worlds. The third aspect of the first security solution introduces a decentralised authentication mechanism. The correspondent requests the authentication data from both the mobile node and home agent. The mobile sends the data in plain text, which could be encrypted with the binding key and the home agent sends a hash of the data. The correspondent then converts the data so both are hashes and compares them. If they are the same, authentication is successful. This provides device and user authentication which when combined with Cryptographically Generated Addresses and Return Routability create a robust security solution called the Distributed Authentication Protocol. The second new technique was designed to provide an enhancement to a current security solution. Dual Identity Return Routability builds on the concept of Return Routability by providing two Mobile IPv6 addresses on a mobile device, giving the user two separate identities. After establishing address ownership with Cryptographically Generated Addresses, Dual Identity Return Routability would then send security data to both identities, each on a separate network and each having heir own home agents, and the mobile node would then combine them together to create the binding key allowing the binding update to be sent securely to the correspondent node. This technique provides protection against address spoofing as an attacker needs two separate ip addresses, which are linked together. Spoofing only a single address will not pass this security solution. One drawback of the security techniques described, however, is that none of them provide location privacy to hide the users IP address from attackers. An attacker cannot mount a direct attack if the user is invisible. The third new security solution designed is Mobile Home Agents. These are software agents, which provide location privacy to the mobile node by acting as a proxy between it and the network. The Mobile Home Agent resides on the point of attachment and migrates to a new point of attachment at the same time as the mobile node. This provides reduced latency communication and a secure environment for the mobile node. These solutions can be used separately or combined together to form a super security solution, which is demonstrated in this thesis and attempts to provide proof of address ownership, reachability, user and device authentication, location privacy and reduction in communication latency. All these security features are design to protect against one the most devastating attacks in Mobile IPv6, the false binding update, which can allow an attacker to impersonate and deny service to the mobile node by redirecting all data packets to itself. The solutions are all simulated with different scenarios and network configurations and with a variety of attacks, which attempt to send a false binding update to the correspondent node. The results were then collected and analysed to provide conclusive proof that the proposed solutions are effective and robust in protecting against the false binding updates creating a safe and secure network for all

Towards Practical Access Control and Usage Control on the Cloud using Trusted Hardware

Cloud-based platforms have become the principle way to store, share, and synchronize files online. For individuals and organizations alike, cloud storage not only provides resource scalability and on-demand access at a low cost, but also eliminates the necessity of provisioning and maintaining complex hardware installations. Unfortunately, because cloud-based platforms are frequent victims of data breaches and unauthorized disclosures, data protection obliges both access control and usage control to manage user authorization and regulate future data use. Encryption can ensure data security against unauthorized parties, but complicates file sharing which now requires distributing keys to authorized users, and a mechanism that prevents revoked users from accessing or modifying sensitive content. Further, as user data is stored and processed on remote ma- chines, usage control in a distributed setting requires incorporating the local environmental context at policy evaluation, as well as tamper-proof and non-bypassable enforcement. Existing cryptographic solutions either require server-side coordination, offer limited flexibility in data sharing, or incur significant re-encryption overheads on user revocation. This combination of issues are ill-suited within large-scale distributed environments where there are a large number of users, dynamic changes in user membership and access privileges, and resources are shared across organizational domains. Thus, developing a robust security and privacy solution for the cloud requires: fine-grained access control to associate the largest set of users and resources with variable granularity, scalable administration costs when managing policies and access rights, and cross-domain policy enforcement. To address the above challenges, this dissertation proposes a practical security solution that relies solely on commodity trusted hardware to ensure confidentiality and integrity throughout the data lifecycle. The aim is to maintain complete user ownership against external hackers and malicious service providers, without losing the scalability or availability benefits of cloud storage. Furthermore, we develop a principled approach that is: (i) portable across storage platforms without requiring any server-side support or modifications, (ii) flexible in allowing users to selectively share their data using fine-grained access control, and (iii) performant by imposing modest overheads on standard user workloads. Essentially, our system must be client-side, provide end-to-end data protection and secure sharing, without significant degradation in performance or user experience. We introduce NeXUS, a privacy-preserving filesystem that enables cryptographic protection and secure file sharing on existing network-based storage services. NeXUS protects the confidentiality and integrity of file content, as well as file and directory names, while mitigating against rollback attacks of the filesystem hierarchy. We also introduce Joplin, a secure access control and usage control system that provides practical attribute-based sharing with decentralized policy administration, including efficient revocation, multi-domain policies, secure user delegation, and mandatory audit logging. Both systems leverage trusted hardware to prevent the leakage of sensitive material such as encryption keys and access control policies; they are completely client-side, easy to install and use, and can be readily deployed across remote storage platforms without requiring any server-side changes or trusted intermediary. We developed prototypes for NeXUS and Joplin, and evaluated their respective overheads in isolation and within a real-world environment. Results show that both prototypes introduce modest overheads on interactive workloads, and achieve portability across storage platforms, including Dropbox and AFS. Together, NeXUS and Joplin demonstrate that a client-side solution employing trusted hardware such as Intel SGX can effectively protect remotely stored data on existing file sharing services

Security mechanisms for next-generation mobile networks

Basic concepts and definitions -- Motivation and research challenges -- Research objectives -- Mobile value-added service access -- UMTS access security -- DoS attacks in mobile networks -- A lightweight mobile service access based on reusable tickets -- Background work and motivation -- Service access through tickets -- System security analysis -- Comparisons with related work -- Enhancing UMTS AKA with vector combination -- Overview of UMTS AKA -- UMTS AKA weaknesses- -- Vector combination based AKA -- Security analysis of VC-AKA -- Mobility-oriented AKA in UMTS -- Mobility-oriented authentication -- Security analysis of MO-AKA -- A fine-grained puzzle against DOS attacks -- Quasi partial collision -- Fine-grained control over difficulties -- Lightweight to mobile devices -- Against replay attacks -- Confidentiality, integrity and user privacy