Simulated penetration testing and mitigation analysis

Da Unternehmensnetzwerke und Internetdienste stetig komplexer werden, wird es immer schwieriger, installierte Programme, Schwachstellen und Sicherheitsprotokolle zu überblicken. Die Idee hinter simuliertem Penetrationstesten ist es, Informationen über ein Netzwerk in ein formales Modell zu transferiern und darin einen Angreifer zu simulieren. Diesem Modell fügen wir einen Verteidiger hinzu, der mittels eigener Aktionen versucht, die Fähigkeiten des Angreifers zu minimieren. Dieses zwei-Spieler Handlungsplanungsproblem nennen wir Stackelberg planning. Ziel ist es, Administratoren, Penetrationstestern und der Führungsebene dabei zu helfen, die Schwachstellen großer Netzwerke zu identifizieren und kosteneffiziente Gegenmaßnahmen vorzuschlagen. Wir schaffen in dieser Dissertation erstens die formalen und algorithmischen Grundlagen von Stackelberg planning. Indem wir dabei auf klassischen Planungsproblemen aufbauen, können wir von gut erforschten Heuristiken und anderen Techniken zur Analysebeschleunigung, z.B. symbolischer Suche, profitieren. Zweitens entwerfen wir einen Formalismus für Privilegien-Eskalation und demonstrieren die Anwendbarkeit unserer Simulation auf lokale Computernetzwerke. Drittens wenden wir unsere Simulation auf internetweite Szenarien an und untersuchen die Robustheit sowohl der E-Mail-Infrastruktur als auch von Webseiten. Viertens ermöglichen wir mittels webbasierter Benutzeroberflächen den leichten Zugang zu unseren Tools und Analyseergebnissen.As corporate networks and Internet services are becoming increasingly more complex, it is hard to keep an overview over all deployed software, their potential vulnerabilities, and all existing security protocols. Simulated penetration testing was proposed to extend regular penetration testing by transferring gathered information about a network into a formal model and simulate an attacker in this model. Having a formal model of a network enables us to add a defender trying to mitigate the capabilities of the attacker with their own actions. We name this two-player planning task Stackelberg planning. The goal behind this is to help administrators, penetration testing consultants, and the management level at finding weak spots of large computer infrastructure and suggesting cost-effective mitigations to lower the security risk. In this thesis, we first lay the formal and algorithmic foundations for Stackelberg planning tasks. By building it in a classical planning framework, we can benefit from well-studied heuristics, pruning techniques, and other approaches to speed up the search, for example symbolic search. Second, we design a theory for privilege escalation and demonstrate the applicability of our framework to local computer networks. Third, we apply our framework to Internet-wide scenarios by investigating the robustness of both the email infrastructure and the web. Fourth, we make our findings and our toolchain easily accessible via web-based user interfaces

Factoring as a Service

The difficulty of integer factorization is fundamental to modern cryptographic security using RSA encryption and signatures. Although a 512-bit RSA modulus was first factored in 1999, 512-bit RSA remains surprisingly common in practice across many cryptographic protocols. Popular understanding of the difficulty of 512-bit factorization does not seem to have kept pace with developments in computing power. In this paper, we optimize the CADO-NFS and Msieve implementations of the number field sieve for use on the Amazon Elastic Compute Cloud platform, allowing a non-expert to factor 512-bit RSA public keys in under four hours for \$75. We go on to survey the RSA key sizes used in popular protocols, finding hundreds or thousands of deployed 512-bit RSA keys in DNSSEC, HTTPS, IMAP, POP3, SMTP, DKIM, SSH, and PGP

Shielding the Grid World: An Overview

Continues research and development efforts within the Grid community have produced protocols, services, and tools that address the challenges arising when we seek to build scalable virtual organizations (VOs). The technologies that have evolved from the Grid community include security solutions that support management of credentials and policies when computations span multiple institutions; resource management protocols and services that support secure remote access to computing and data resources and the co-allocation of multiple resources; information query protocols and services that provide configuration and status information about resources, organizations, and services; and data management services that locate and transport datasets between storage systems and applications

Padding Ain't Enough: Assessing the Privacy Guarantees of Encrypted DNS

DNS over TLS (DoT) and DNS over HTTPS (DoH) encrypt DNS to guard user privacy by hiding DNS resolutions from passive adversaries. Yet, past attacks have shown that encrypted DNS is still sensitive to traffic analysis. As a consequence, RFC 8467 proposes to pad messages prior to encryption, which heavily reduces the characteristics of encrypted traffic. In this paper, we show that padding alone is insufficient to counter DNS traffic analysis. We propose a novel traffic analysis method that combines size and timing information to infer the websites a user visits purely based on encrypted and padded DNS traces. To this end, we model DNS sequences that capture the complexity of websites that usually trigger dozens of DNS resolutions instead of just a single DNS transaction. A closed world evaluation based on the Alexa top-10k websites reveals that attackers can deanonymize at least half of the test traces in 80.2% of all websites, and even correctly label all traces for 32.0% of the websites. Our findings undermine the privacy goals of state-of-the-art message padding strategies in DoT/DoH. We conclude by showing that successful mitigations to such attacks have to remove the entropy of inter-arrival timings between query responses

Measuring And Securing Cryptographic Deployments

This dissertation examines security vulnerabilities that arise due to communication failures and incentive mismatches along the path from cryptographic algorithm design to eventual deployment. I present six case studies demonstrating vulnerabilities in real-world cryptographic deployments. I also provide a framework with which to analyze the root cause of cryptographic vulnerabilities by characterizing them as failures in four key stages of the deployment process: algorithm design and cryptanalysis, standardization, implementation, and endpoint deployment. Each stage of this process is error-prone and influenced by various external factors, the incentives of which are not always aligned with security. I validate the framework by applying it to the six presented case studies, tracing each vulnerability back to communication failures or incentive mismatches in the deployment process. To curate these case studies, I develop novel techniques to measure both existing and new cryptographic attacks, and demonstrate the widespread impact of these attacks on real-world systems through measurement and cryptanalysis. While I do not claim that all cryptographic vulnerabilities can be described with this framework, I present a non-trivial (in fact substantial) number of case studies demonstrating that this framework characterizes the root cause of failures in a diverse set of cryptographic deployments

ROVER: a DNS-based method to detect and prevent IP hijacks

2013 Fall.Includes bibliographical references.The Border Gateway Protocol (BGP) is critical to the global internet infrastructure. Unfortunately BGP routing was designed with limited regard for security. As a result, IP route hijacking has been observed for more than 16 years. Well known incidents include a 2008 hijack of YouTube, loss of connectivity for Australia in February 2012, and an event that partially crippled Google in November 2012. Concern has been escalating as critical national infrastructure is reliant on a secure foundation for the Internet. Disruptions to military, banking, utilities, industry, and commerce can be catastrophic. In this dissertation we propose ROVER (Route Origin VERification System), a novel and practical solution for detecting and preventing origin and sub-prefix hijacks. ROVER exploits the reverse DNS for storing route origin data and provides a fail-safe, best effort approach to authentication. This approach can be used with a variety of operational models including fully dynamic in-line BGP filtering, periodically updated authenticated route filters, and real-time notifications for network operators. Our thesis is that ROVER systems can be deployed by a small number of institutions in an incremental fashion and still effectively thwart origin and sub-prefix IP hijacking despite non-participation by the majority of Autonomous System owners. We then present research results supporting this statement. We evaluate the effectiveness of ROVER using simulations on an Internet scale topology as well as with tests on real operational systems. Analyses include a study of IP hijack propagation patterns, effectiveness of various deployment models, critical mass requirements, and an examination of ROVER resilience and scalability

SEINIT Security for Heterogeneous Mobile Network Services

This paper presents a model for securing mobile services using heterogeneous access networks, and implementing sample solutions using this framework. This is a project that is defining new security models and policies to address the new issues of the pervasive computing world. The security models and policies are implemented over IPv6 infrastructures to cover various business cases and assessed against real life scenarios. SEINIT is developing a trusted and dependable security framework with the end-user as the focus

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

Addressless: A New Internet Server Model to Prevent Network Scanning

Eliminating unnecessary exposure is a principle of server security. The huge IPv6 address space enhances security by making scanning infeasible, however, with recent advances of IPv6 scanning technologies, network scanning is again threatening server security. In this paper, we propose a new model named addressless server, which separates the server into an entrance module and a main service module, and assigns an IPv6 prefix instead of an IPv6 address to the main service module. The entrance module generates a legitimate IPv6 address under this prefix by encrypting the client address, so that the client can access the main server on a destination address that is different in each connection. In this way, the model provides isolation to the main server, prevents network scanning, and minimizes exposure. Moreover it provides a novel framework that supports flexible load balancing, high-availability, and other desirable features. The model is simple and does not require any modification to the client or the network. We implement a prototype and experiments show that our model can prevent the main server from being scanned at a slight performance cost