Robustness Testing and Hardening of CORBA ORB Implementations

Before using CORBA (Common Object Request Broker Architecture) applications in mission-critical scenarios, it is important to understand the robustness of the Object Request Broker (ORB) being used, which forms the platform for CORBA applications. We have extended the Ballista software testing technique to test the exception-handling robustness of C++ ORB client-side application interfaces, and have tested two major versions of three ORB implementations on two operating systems, yielding robustness failure rates ranging from 26% to 42%. To improve ORB robustness, we also propose a probing method to harden object and pseudo-object related data types against exceptional inputs. Using these probes on omniORB 2.8 has proven to be effective in eliminating some cases of robustness failures found during testing. These results suggest that CORBA implementations currently have significant robustness vulnerabilities, but that some important classes of problems can be overcome with better exception-handling approaches.</p

Vulnerability detection in device drivers

Tese de doutoramento, Informática (Ciência da Computação), Universidade de Lisboa, Faculdade de Ciências, 2017The constant evolution in electronics lets new equipment/devices to be regularly made available on the market, which has led to the situation where common operating systems (OS) include many device drivers(DD) produced by very diverse manufactures. Experience has shown that the development of DD is error prone, as a majority of the OS crashes can be attributed to flaws in their implementation. This thesis addresses the challenge of designing methodologies and tools to facilitate the detection of flaws in DD, contributing to decrease the errors in this kind of software, their impact in the OS stability, and the security threats caused by them. This is especially relevant because it can help developers to improve the quality of drivers during their implementation or when they are integrated into a system. The thesis work started by assessing how DD flaws can impact the correct execution of the Windows OS. The employed approach used a statistical analysis to obtain the list of kernel functions most used by the DD, and then automatically generated synthetic drivers that introduce parameter errors when calling a kernel function, thus mimicking a faulty interaction. The experimental results showed that most targeted functions were ineffective in the defence of the incorrect parameters. A reasonable number of crashes and a small number of hangs were observed suggesting a poor error containment capability of these OS functions. Then, we produced an architecture and a tool that supported the automatic injection of network attacks in mobile equipment (e.g., phone), with the objective of finding security flaws (or vulnerabilities) in Wi-Fi drivers. These DD were selected because they are of easy access to an external adversary, which simply needs to create malicious traffic to exploit them, and therefore the flaws in their implementation could have an important impact. Experiments with the tool uncovered a previously unknown vulnerability that causes OS hangs, when a specific value was assigned to the TIM element in the Beacon frame. The experiments also revealed a potential implementation problem of the TCP-IP stack by the use of disassociation frames when the target device was associated and authenticated with a Wi-Fi access point. Next, we developed a tool capable of registering and instrumenting the interactions between a DD and the OS. The solution used a wrapper DD around the binary of the driver under test, enabling full control over the function calls and parameters involved in the OS-DD interface. This tool can support very diverse testing operations, including the log of system activity and to reverse engineer the driver behaviour. Some experiments were performed with the tool, allowing to record the insights of the behaviour of the interactions between the DD and the OS, the parameter values and return values. Results also showed the ability to identify bugs in drivers, by executing tests based on the knowledge obtained from the driver’s dynamics. Our final contribution is a methodology and framework for the discovery of errors and vulnerabilities in Windows DD by resorting to the execution of the drivers in a fully emulated environment. This approach is capable of testing the drivers without requiring access to the associated hardware or the DD source code, and has a granular control over each machine instruction. Experiments performed with Off the Shelf DD confirmed a high dependency of the correctness of the parameters passed by the OS, identified the precise location and the motive of memory leaks, the existence of dormant and vulnerable code.A constante evolução da eletrónica tem como consequência a disponibilização regular no mercado de novos equipamentos/dispositivos, levando a uma situação em que os sistemas operativos (SO) mais comuns incluem uma grande quantidade de gestores de dispositivos (GD) produzidos por diversos fabricantes. A experiência tem mostrado que o desenvolvimento dos GD é sujeito a erros uma vez que a causa da maioria das paragens do SO pode ser atribuída a falhas na sua implementação. Esta tese centra-se no desafio da criação de metodologias e ferramentas que facilitam a deteção de falhas nos GD, contribuindo para uma diminuição nos erros neste tipo de software, o seu impacto na estabilidade do SO, e as ameaças de segurança por eles causadas. Isto é especialmente relevante porque pode ajudar a melhorar a qualidade dos GD tanto na sua implementação como quando estes são integrados em sistemas. Este trabalho inicia-se com uma avaliação de como as falhas nos GD podem levar a um funcionamento incorreto do SO Windows. A metodologia empregue usa uma análise estatística para obter a lista das funções do SO que são mais utilizadas pelos GD, e posteriormente constrói GD sintéticos que introduzem erros nos parâmetros passados durante a chamada às funções do SO, e desta forma, imita a integração duma falta. Os resultados das experiências mostraram que a maioria das funções testadas não se protege eficazmente dos parâmetros incorretos. Observou-se a ocorrência de um número razoável de paragens e um pequeno número de bloqueios, o que sugere uma pobre capacidade das funções do SO na contenção de erros. Posteriormente, produzimos uma arquitetura e uma ferramenta que suporta a injeção automática de ataques em equipamentos móveis (e.g., telemóveis), com o objetivo de encontrar falhas de segurança (ou vulnerabilidades) em GD de placas de rede Wi-Fi. Estes GD foram selecionados porque são de fácil acesso a um atacante remoto, o qual apenas necessita de criar tráfego malicioso para explorar falhas na sua implementação podendo ter um impacto importante. As experiências realizadas com a ferramenta revelaram uma vulnerabilidade anteriormente desconhecida que provoca um bloqueio no SO quando é atribuído um valor específico ao campo TIM da mensagem de Beacon. As experiências também revelaram um potencial problema na implementação do protocolo TCP-IP no uso das mensagens de desassociação quando o dispositivo alvo estava associado e autenticado com o ponto de acesso Wi-Fi. A seguir, desenvolvemos uma ferramenta com a capacidade de registar e instrumentar as interações entre os GD e o SO. A solução usa um GD que envolve o código binário do GD em teste, permitindo um controlo total sobre as chamadas a funções e aos parâmetros envolvidos na interface SO-GD. Esta ferramenta suporta diversas operações de teste, incluindo o registo da atividade do sistema e compreensão do comportamento do GD. Foram realizadas algumas experiências com esta ferramenta, permitindo o registo das interações entre o GD e o SO, os valores dos parâmetros e os valores de retorno das funções. Os resultados mostraram a capacidade de identificação de erros nos GD, através da execução de testes baseados no conhecimento da dinâmica do GD. A nossa contribuição final é uma metodologia e uma ferramenta para a descoberta de erros e vulnerabilidades em GD Windows recorrendo à execução do GD num ambiente totalmente emulado. Esta abordagem permite testar GD sem a necessidade do respetivo hardware ou o código fonte, e possuí controlo granular sobre a execução de cada instrução máquina. As experiências realizadas com GD disponíveis comercialmente confirmaram a grande dependência que os GD têm nos parâmetros das funções do SO, e identificaram o motivo e a localização precisa de fugas de memória, a existência de código não usado e vulnerável

Integrating legacy mainframe systems: architectural issues and solutions

For more than 30 years, mainframe computers have been the backbone of computing systems throughout the world. Even today it is estimated that some 80% of the worlds' data is held on such machines. However, new business requirements and pressure from evolving technologies, such as the Internet is pushing these existing systems to their limits and they are reaching breaking point. The Banking and Financial Sectors in particular have been relying on mainframes for the longest time to do their business and as a result it is they that feel these pressures the most. In recent years there have been various solutions for enabling a re-engineering of these legacy systems. It quickly became clear that to completely rewrite them was not possible so various integration strategies emerged. Out of these new integration strategies, the CORBA standard by the Object Management Group emerged as the strongest, providing a standards based solution that enabled the mainframe applications become a peer in a distributed computing environment. However, the requirements did not stop there. The mainframe systems were reliable, secure, scalable and fast, so any integration strategy had to ensure that the new distributed systems did not lose any of these benefits. Various patterns or general solutions to the problem of meeting these requirements have arisen and this research looks at applying some of these patterns to mainframe based CORBA applications. The purpose of this research is to examine some of the issues involved with making mainframebased legacy applications inter-operate with newer Object Oriented Technologies

Test et évaluation de la robustesse de la couche fonctionnelle d'un robot autonome

La mise en oeuvre de systèmes autonomes nécessite le développement et l'utilisation d'architectures logicielles multi-couches qui soient adaptées. Typiquement, une couche fonctionnelle renferme des modules en charge de commander les éléments matériels du système et de fournir des services élémentaires. Pour être robuste, la couche fonctionnelle doit être dotée de mécanismes de protection vis-à-vis de requêtes erronées ou inopportunes issues de la couche supérieure. Nous présentons une méthodologie pour tester la robustesse de ces mécanismes. Nous définissons un cadre général pour évaluer la robustesse d'une couche fonctionnelle par la caractérisation de son comportement vis-à-vis de requêtes inopportunes. Nous proposons également un environnement de validation basé sur l'injection de fautes dans le logiciel de commande d'un robot simulé. Un grand nombre de cas de tests est généré automatiquement par la mutation d'une séquence de requêtes valides. Les statistiques descriptives des comportements en présence de requêtes inopportunes sont analysées afin d'évaluer la robustesse du système sous test. ABSTRACT : The implementation of autonomous systems requires the development and the using of multi-layer software architecture. Typically, a functional layer contains several modules that control the material of the system and provide elementary services. To be robust, the functional layer must be implemented with protection mechanisms with respect to erroneous or inopportune requests sent from the superior layer. We present a methodology for robustness testing these mechanisms. We define a general framework to evaluate the robustness of a functional layer by characterizing its behavior with respect to inappropriate requests. We also propose an validation environment based on fault injection in the control software of a simulated robot. A great number of test cases is generated automatically by the mutation of a sequence of valid requests. The descriptive statistics of the behaviors in the presence of inappropriate requests are analyzed in order to evaluate the robustness of the system under test

Resilience-Building Technologies: State of Knowledge -- ReSIST NoE Deliverable D12

This document is the first product of work package WP2, "Resilience-building and -scaling technologies", in the programme of jointly executed research (JER) of the ReSIST Network of Excellenc

Étalonnage de la sûreté de fonctionnement des systèmes d’exploitation – Spécifications et mise en oeuvre

Les développeurs des systèmes informatiques, y compris critiques, font souvent appel à des systèmes d’exploitation sur étagère. Cependant, un mauvais fonctionnement d’un système d’exploitation peut avoir un fort impact sur la sûreté de fonctionnement du système global, d’où la nécessité de trouver des moyens efficaces pour caractériser sa sûreté de fonctionnement. Dans cette thèse, nous étudions l’étalonnage de la sûreté de fonctionnement des systèmes d’exploitation par rapport aux comportements défectueux de l’application. Nous spécifions les propriétés qu’un étalon de sûreté de fonctionnement doit satisfaire. Après, nous spécifions les mesures et la mise en oeuvre des trois étalons destinés à comparer la sûreté de fonctionnement de différents systèmes d’exploitation. Ensuite, nous développons les prototypes des trois étalons. Ces prototypes servent à comparer les différents systèmes d’exploitation des familles Windows et Linux, et pour montrer la satisfaction des propriétés identifiées. ABSTRACT : System developers are increasingly resorting to off-the-shelf operating systems, even in critical application domains. Any malfunction of the operating system may have a strong impact on the dependability of the global system. Therefore, it is important to make available information about the operating systems dependability. In our work, we aim to specify dependability benchmarks to characterize the operating systems with respect to the faulty behavior of the application. We specify three benchmarks intended for comparing the dependability of operating systems belonging to different families. We specify the set of measures and the procedures to be followed after defining the set of properties that a dependability benchmark should satisfy. After, we present implemented prototypes of these benchmarks. They are used to compare the dependability of operating systems belonging to Windows and Linux, and to show that our benchmarks satisfy the identified properties

Caractérisation de la sûreté de fonctionnement des systèmes d'exploitation en présence de pilotes défaillants

Les pilotes de périphériques composent désormais une part essentielle des systèmes d’exploitation. Plusieurs études montrent qu’ils sont fréquemment à l’origine des dysfonctionnements des systèmes opératoires. Dans ce mémoire, nous présentons une méthode pour l’évaluation de la robustesse des noyaux face aux comportements anormaux des pilotes de périphériques. Pour cela, après avoir analysé et précisé les caractéristiques des échanges entre les pilotes et le noyau (DPI - Driver Programming Interface), nous proposons une technique originale d’injection de fautes basée sur la corruption des paramètres des fonctions manipulées au niveau de cette interface. Nous définissons différentes approches pour l’analyse et l’interprétation des résultats observés pour obtenir des mesures objectives de sûreté de fonctionnement. Ces mesures permettent la prise en compte de différents points de vue afin de répondre aux besoins réels de l’utilisateur. Enfin, nous illustrons et validons l’applicabilité de cette méthode par sa mise en oeuvre dans le cadre d’un environnement expérimental sous Linux. La méthode proposée contribue à la caractérisation de la sûreté de fonctionnement des noyaux vis-à-vis des défaillances des pilotes du système. L’impact des résultats est double : a) permettre au développeur de tels logiciels d’identifier les faiblesses potentielles affectant la sûreté de fonctionnement du système, b) aider un intégrateur dans le choix du composant le mieux adapté à ses besoins