Heap . . . Hop! Heap Is Also Vulnerable

International audienceSeveral logical attacks against Java based smart card have been published recently. Most of them are based on the hypothesis that the type verification was not performed, thus allowing to obtain dynamically a type confusion. To mitigate such attacks, typed stack have been introduced on recent smart card. We propose here a new attack path for performing a type confusion even in presence of a typed stack. Then we propose using a Fault Tree Analysis a way to design efficiently counter measure in a top down approach. These counter measures are then evaluated on a Java Card virtual machin

Evaluation of the Ability to Transform SIM Applications into Hostile Applications

Part 1: Smart Cards System SecurityInternational audienceThe ability of Java Cards to withstand attacks is based on software and hardware countermeasures, and on the ability of the Java platform to check the correct behavior of Java code (by using byte code verification). Recently, the idea of combining logical attacks with a physical attack in order to bypass byte code verification has emerged. For instance, correct and legitimate Java Card applications can be dynamically modified on-card using a laser beam. Such applications become mutant applications, with a different control flow from the original expected behaviour. This internal change could lead to bypass controls and protections and thus offer illegal access to secret data and operations inside the chip. This paper presents an evaluation of the application ability to become mutant and a new countermeasure based on the runtime checks of the application control flow to detect the deviant mutations

Combined Software and Hardware Attacks on the Java Card Control Flow

Part 7: Java Card SecurityInternational audienceThe Java Card uses two components to ensure the security of its model. On the one hand, the byte code verifier (BCV) checks, during an applet installation, if the Java Card security model is ensured. This mechanism may not be present in the card. On the other hand, the firewall dynamically checks if there is no illegal access. This paper describes two attacks to modify the Java Card control flow and to execute our own malicious byte code. In the first attack, we use a card without embedded security verifier and we show how it is simple to change the return address of a current function. In the second attack, we consider the hypothesis that the card embeds a partial implementation of a BCV. With the help of a laser beam, we are able to change the execution flow

Memory Forensics of a Java Card Dump

International audienceNowadays several papers have shown the ability to dump the EEPROM area of several Java Cards leading to the disclosure of already loaded applet and data structure of the card. Such a reverse engineering process is costly and prone to errors. Currently there are no tools available to help the process. We propose here an approach to find in the raw data obtained after a dump, the area containing the code and the data. Then, once the code area has been identified, we propose to rebuilt the original binary Cap file in order to be able to obtain the source code of the applet stored in the card

Formal Verification of Security Protocol Implementations: A Survey

Automated formal verification of security protocols has been mostly focused on analyzing high-level abstract models which, however, are significantly different from real protocol implementations written in programming languages. Recently, some researchers have started investigating techniques that bring automated formal proofs closer to real implementations. This paper surveys these attempts, focusing on approaches that target the application code that implements protocol logic, rather than the libraries that implement cryptography. According to these approaches, libraries are assumed to correctly implement some models. The aim is to derive formal proofs that, under this assumption, give assurance about the application code that implements the protocol logic. The two main approaches of model extraction and code generation are presented, along with the main techniques adopted for each approac

Lazart: A Symbolic Approach for Evaluation the Robustness of Secured Codes against Control Flow Injections

International audienceIn the domain of smart cards, secured devices must be protected against high level attack potential [1]. According to norms such as the Common Criteria [2], the vulnerability analysis must cover the current state-of-the-art in term of attacks. Nowadays, a very classical type of attack is fault injection, conducted by means of laser based techniques. We propose a global approach, called Lazart, to evaluate code robustness against fault injections targeting control flow modifications. The originality of Lazart is twofolds. First, we encompass the evaluation process as a whole: starting from a fault model, we produce (or establish the absence of) attacks, taking into consideration software countermeasures. Furthermore, according to the near state-of-the-art, our methodology takes into account multiple transient fault injections and their combinatory. The proposed approach is supported by an effective tool suite based on the LLVM format [3] and the KLEE symbolic test generator [4]

Contributions à la sécurité des Java Card

La Java Card est aujourd’hui le type de cartes à puce le plus déployé dans le milieu bancaire ou dans la téléphonie mobile. Outres la présence de nombreuses contre-mesures physiques pour protéger le microprocesseur contre les attaques externes, la machine virtuelle Java Card possède un ensemble de mécanismes (comme le vérificateur de bytecode et le pare-feu) qui, combinés avec le typage du langage Java, offrent des propriétés d’isolation forte des applications (applets) vis-à-vis de l’exécution de la machine virtuelle Java Card.Mais l’évolution des attaques logicielles par confusion de type et par des moyens physiques a montré des limitations au modèle d’isolation de la machine virtuelle. Dans un premier temps, plusieurs travaux montrent des nouvelles menaces logiques, physiques et hybrides afin de lever des secrets enfouis dans des instances de Java Card en exploitant les applications chargées comme cibles et vecteurs d’attaque. Par la suite, plusieurs stratégies de contre-mesures sont construites selon deux points de vue. D’une part des protections réactives (contre les attaques en fautes) et proactives (par mise à jour dynamique) sont intégrées dans la machine virtuelle Java Card. D’autre part, des solutions d’analyse de code permettant d’aider le développeur sont évaluées afin de renforcer la sécurité des applets contre des faiblesses de développement ou les exploitations possibles du bytecode par des attaques en faute

The ultimate control flow transfer in a Java based smart card

International audienceRecently, researchers published several attacks on smart cards. Among these, software attacks are the most affordable, they do not require specific hardware (laser, EM probe, etc.). Such attacks succeed to modify a sensitive system element which offers access to the smart card assets. To prevent that, smart card manufacturers embed dedicated countermeasures that aim to protect the sensitive system elements. We present a generic approach based on a Control Flow Transfer (CFT) attack to modify the Java Card program counter. This attack is built on a type confusion using the couple of instructions jsr/ret. Evaluated on different Java Cards, this new attack is a generic CFT exploitation that succeeds on each attacked cards. We present several countermeasures proposed by the literature or implemented by smart card designers and for all of them we explain how to bypass them. Then, we propose to use Attack Countermeasure Tree to develop an effective and affordable countermeasure for this attack