Séminaire SCN

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Séminaire CoaP du 30 mai

Publié le 25/04/2023
Par Olivier Levillain

Dans CoaP.

Dans le cadre de notre séminaire « La Cybersécurité sur un plateau » (Cybersecurity on a Plate), nous aurons deux interventions le 30 mai. Le séminaire CoaP aura lieu à 10h dans le bâtiment IMT/TP/TSP, en salle 3.A213.

Michaël Marcozzi (CEA) - Fine-Grained Coverage-Based Fuzzing

Fuzzing is a popular software testing method that discovers vulnerabilities by massively feeding target applications with automatically generated inputs. Many state-of-art fuzzers use branch coverage as a feedback metric to guide the fuzzing process. The fuzzer retains inputs for further mutation only if branch coverage is increased. However, branch coverage only provides a shallow sampling of program behaviours and hence may discard interesting inputs to mutate. This work aims at taking advantage of the large body of research over defining finer-grained code coverage metrics (such as control-flow, data-flow or mutation coverage) and at evaluating how fuzzing performance is impacted when using these metrics to select interesting inputs for mutation. We propose to make branch coverage-based fuzzers support most fine-grained coverage metrics out of the box (i.e., without changing fuzzer internals). We achieve this by making the test objectives defined by these metrics (such as conditions to activate or mutants to kill) explicit as new branches in the target program. Fuzzing such a modified target is then equivalent to fuzzing the original target, but the fuzzer will also retain inputs covering the additional metrics objectives for mutation. In addition, all the fuzzer mechanisms to penetrate hard-to-cover branches will help covering the additional metrics objectives. We use this approach to evaluate the impact of supporting two fine-grained coverage metrics (multiple condition coverage and weak mutation) over the performance of two state-of-the-art fuzzers (AFL++ and QSYM) with the standard LAVA-M and MAGMA benchmarks. This evaluation suggests that our mechanism for runtime fuzzer guidance, where the fuzzed code is instrumented with additional branches, is effective and could be leveraged to encode guidance from human users or static analysers. Our results also show that the impact of fine-grained metrics over fuzzing performance is hard to predict before fuzzing, and most of the time either neutral or negative. As a consequence, we do not recommend using them to guide fuzzers, except maybe in some possibly favourable circumstances yet to investigate, like for limited parts of the code or to complement classical fuzzing campaigns.

Houda Jmila (TSP) - Analyzing the Vulnerability of Machine Learning-Based IDS to Adversarial Attacks in Cybersecurity

The detection of intrusions is an important aspect of cybersecurity, as it seeks to safeguard computer systems and networks from malicious attacks. While machine learning (ML) techniques have been effective in this field, they face challenges such as the emergence of adversarial attacks that can deceive classifiers. Preventing cybercriminals from exploiting these vulnerabilities is crucial in preventing damage to data and systems. This presentation analyses the vulnerability of both deep learning and shallow classifiers, which are still widely used due to their maturity and ease of implementation, to adversarial attacks in ML-based IDS. Additionally, we explore whether adversarial attacks borrowed from computer vision pose a significant threat to IDS and to what extent realistic adversarial attacks can be generated using these methods.


Séminaire CoaP du 18 Avril

Publié le 31/03/2023
Par Gregory Blanc

Dans CoaP.

Dans le cadre de notre séminaire « La Cybersécurité sur un plateau » (Cybersecurity on a Plate), nous aurons deux interventions le 18 avril. Le séminaire CoaP aura lieu à 10h dans le bâtiment IMT/TP/TSP, en salle 3.A213.

Pierre-Elisée Flory - Comparing Private Set Intersection Various Implementations for Fraud Detection

Banks have to commit answering their customers' privacy concerns while complying to regulation. Sharing information on customer among a Banking consortium is an efficient way to identify fraud at an early stage but requires efficient biometrics matching algorithms to compare two id cards / biometrics template in pictures. Consortium stakeholders may also be competitors and thus need to protect their customer database. Within the Privacy Enhancing Technologies, we have assessed and compared different Secure Multi-Party Computation and in particular Private Set Intersection schemes to mitigate those risks and design a new protocol to allow privacy preserving biometrics templates matching.

Nathanaël Denis - Integrating Usage Control into Distributed Ledger Technology for Internet of Things Privacy

The Internet of Things brings new ways to collect privacy-sensitive data from billions of devices. Well-tailored distributed ledger technologies (DLTs) can provide high transaction processing capacities to IoT devices in a decentralized fashion. However, privacy aspects are often neglected or unsatisfying, with a focus mainly on performance and security. In this paper, we introduce decentralized usage control mechanisms to empower IoT devices to control the data they generate. Usage control defines obligations i.e., actions to be fulfilled to be granted access, and conditions on the system in addition to data dissemination control. The originality of this paper is to consider the usage control system as a component of distributed ledger networks, instead of an external tool. With this integration, both technologies work in synergy, benefiting their privacy, security and performance. We evaluated the performance improvements of integration using the IOTA technology, particularly suitable due to the participation of small devices in the consensus. The results of the tests on a private network show an approximate 90% decrease of the time needed for the UCS to push a transaction and make its access decision in the integrated setting, regardless of the number of nodes in the network.

This contribution is currently under review for publication in a journal.


Séminaire CoaP du 15 février: NVIDIA DOCA hackathon and Adversarial Reachability for Program-level Security Analysis

Publié le 30/01/2023
Par Arthur Tran Van

Dans CoaP.

Dans le cadre de notre séminaire « La Cybersécurité sur un plateau » (Cybersecurity on a Plate), nous aurons deux interventions le 15 février. Le séminaire CoaP aura lieu à 10h dans le bâtiment IMT/TP/TSP, en salle 3.A213.

Romain Ferrari, Louis Cailliot, Julie Sauzedde, Pierre-Elisée Flory - NVIDIA DOCA hackathon

The NVIDIA DOCA hackathon took place on March 21, during NVIDIA 2022 GTC.

The Thales team chose to build a solution upon the DPI acceleration to enable Yara rules, which are used for inspection of files downloaded from the network to identify malware and potential threats. To implement this, Team Thales used a Yara Parser to transform public Yara rules into DPI rules in a Suricata community-based format supported by the DOCA DPI lib. This solution leveraged DOCA DPI functionality to scan the files on the fly as the packets flow through the device.

Soline Ducousso - Adversarial Reachability for Program-level Security Analysis

Many program analysis tools and techniques have been developed to assess program vulnerability. Yet, they are based on the standard concept of reachability and represent an attacker able to craft smart legitimate input, while in practice attackers can be much more powerful, using for instance micro-architectural exploits or fault injection methods. We introduce adversarial reachability , a framework allowing to reason about such advanced attackers and check whether a system is vulnerable or immune to a particular attacker. As equipping the attacker with new capacities significantly increases the state space of the program under analysis, we present a new symbolic exploration algorithm, namely adversarial symbolic execution, injecting faults in a forkless manner to prevent path explosion, together with optimizations dedicated to reduce the number of injections to consider while keeping the same attacker power. Experiments on representative benchmarks from fault injection show that our method significantly reduces the number of adversarial paths to explore, allowing to scale up to 10 faults where prior work timeout for 3 faults. In addition, we analyze the well-tested WooKey's bootloader, and demonstrate the ability of our analysis to find attacks and evaluate countermeasures in real-life security scenarios.

This is joint work with Sébastien Bardin and Marie-Laure Potet.


[Séminaire reporté] Séminaire CoaP du 19 janvier: NVIDIA DOCA hackathon and Adversarial Reachability for Program-level Security Analysis

Publié le 05/01/2023
Par Arthur Tran Van

Dans CoaP.

En raison de l'appel à la grève le 19 janvier, le séminaire est reporté à une date qui doit encore être définie.

Dans le cadre de notre séminaire « La Cybersécurité sur un plateau » (Cybersecurity on a Plate), nous aurons deux interventions le 19 janvier. Le séminaire CoaP aura lieu à 14h dans le bâtiment IMT/TP/TSP, en salle 3.A213.

Romain Ferrari, Louis Cailliot, Julie Sauzedde, Pierre-Elisée Flory - NVIDIA DOCA hackathon

The NVIDIA DOCA hackathon took place on March 21, during NVIDIA 2022 GTC.

The Thales team chose to build a solution upon the DPI acceleration to enable Yara rules, which are used for inspection of files downloaded from the network to identify malware and potential threats. To implement this, Team Thales used a Yara Parser to transform public Yara rules into DPI rules in a Suricata community-based format supported by the DOCA DPI lib. This solution leveraged DOCA DPI functionality to scan the files on the fly as the packets flow through the device.

Soline Ducousso - Adversarial Reachability for Program-level Security Analysis

Many program analysis tools and techniques have been developed to assess program vulnerability. Yet, they are based on the standard concept of reachability and represent an attacker able to craft smart legitimate input, while in practice attackers can be much more powerful, using for instance micro-architectural exploits or fault injection methods. We introduce adversarial reachability , a framework allowing to reason about such advanced attackers and check whether a system is vulnerable or immune to a particular attacker. As equipping the attacker with new capacities significantly increases the state space of the program under analysis, we present a new symbolic exploration algorithm, namely adversarial symbolic execution, injecting faults in a forkless manner to prevent path explosion, together with optimizations dedicated to reduce the number of injections to consider while keeping the same attacker power. Experiments on representative benchmarks from fault injection show that our method significantly reduces the number of adversarial paths to explore, allowing to scale up to 10 faults where prior work timeout for 3 faults. In addition, we analyze the well-tested WooKey's bootloader, and demonstrate the ability of our analysis to find attacks and evaluate countermeasures in real-life security scenarios.

This is joint work with Sébastien Bardin and Marie-Laure Potet.


Séminaire CoaP du 21 novembre

Publié le 08/11/2022
Par Olivier Levillain

Dans CoaP.

Dans le cadre de notre séminaire « La Cybersécurité sur un plateau » (Cybersecurity on a Plate), nous recevrons le 21 novembre deux intervenants :

  • Aina Toky Rasoamanana, doctorant à Télécom SudParis, qui présentera ses travaux sur l'inférence de machines à états d'implémentations du protocole TLS.
  • Mohamad Mansouri, doctorant CIFRE à EURECOM / Thales, qui présentera ses travaux sur l'agrégation sécurisée et tolérante aux pannes pour l'apprentissage fédéré.

Le séminaire CoaP aura lieu à 14h dans le bâtiment IMT/TP/TSP, en salle 3.A405.

Aina Toky Rasoamanana - Towards a Systematic and Automatic Use of State Machine Inference to Uncover Security Flaws and Fingerprint TLS Stacks

TLS is a well-known and thoroughly studied security protocol. In this paper, we focus on a specific class of vulnerabilities affecting TLS implementations, state machine errors. These vulnerabilities are caused by differences in interpreting the standard and correspond to deviations from the specifications, e.g. accepting invalid messages, or accepting valid messages out of sequence. We develop a systematic methodology to infer the state machines of major TLS stacks from stimuli and observations, and to study their evolution across revisions. We use the L* algorithm to compute state machines corresponding to different execution scenarios. We reproduce several known vulnerabilities (denial of service, authentication bypasses), and uncover new ones. We also show that state machine inference is efficient and practical for integration within a continuous integration pipeline, to help find new vulnerabilities or deviations introduced during development.

With our systematic black-box approach, we study over 400 different versions of server and client implementations in various scenarios (protocol version, options). Using the resulting state machines, we propose a robust algorithm to fingerprint TLS stacks. To the best of our knowledge, this is the first application of this approach on such a broad perimeter, in terms of number of TLS stacks, revisions, or execution scenarios studied.

This work has been published at ESORICS 2022.

Mohamad Mansouri - Learning from Failures: Secure and Fault-Tolerant Secure Aggregation for Federated Learning

Federated learning allows multiple parties to collaboratively train a global machine learning (ML) model without sharing their private datasets. To make sure that these local datasets are not leaked, existing works propose to rely on a secure aggregation scheme that allows parties to encrypt their model updates before sending them to the central server that aggregates the encrypted inputs.

In this work, we design and evaluate a new secure and fault-tolerant aggregation scheme for federated learning that is robust against client failures. We first develop a threshold-variant of the secure aggregation scheme proposed by Joye and Libert. Using this new building block together with a dedicated decentralized key management scheme and an input encoding solution, we design a privacy-preserving federated learning protocol that, when executed among n clients, can recover from up to n/3 failures. Our solution is secure against a malicious aggregator who can manipulate messages to learn clients' individual inputs. We show that our solution outperforms the state-of-the-art fault-tolerant secure aggregation schemes in terms of computation cost on the client. For example, with an ML model of 100K parameters, trained with 600 clients, our protocol is 5.5x faster (1.6x faster in case of 180 clients drop).

This work will appear in ACSAC’22.


Séminaire des étudiants et anciens le 11 octobre 22

Publié le 11/10/2022
Par Olivier Levillain

Dans Anciens.

Ce séminaire, destiné aux étudiants de Télécom SudParis en cybersécurité et aux anciens élèves, aura lieu à Palaiseau, dans le bâtiment IMT/TP/TSP, à partir de 13h30. Le séminaire aura lieu en Amphi 5. Il sera suivi, à partir de 18h30, d'un cocktail dînatoire à l'Entrepôtes 19, près du bâtiment TP/TSP.

Programme

  • 13h30 : Café
  • 14h : Grégory Blanc, Christophe Kiennert et Olivier Levillain - Accueil
  • 14h15 : Constance Chou (Thales) - Web Application Firewall : enjeux, fonctionnement et étude
  • 14h45 : Martin Spiering, Matthieu Touloucanon et Quentin Michaud (HackademINT) - 404 CTF
  • 15h15 : Ministère de l'Intérieur - Analyse de flux chiffré en entreprise pour la détection d'incident de sécurité
  • 15h45 : Pause
  • 16h30 : Amré Abouali (Cybershen) - Ancien RSSI & Entrepreneur
  • 17h : Olivier Levillain (TSP) - Influence de la qualité des spécifications sur la sécurité logicielle
  • 17h30 : Rump Session
  • 18h30 : Cocktail dînatoire à l'Entrepôtes 19 près du bâtiment TP/TSP

Constance Chou - Web Application Firewall : enjeux, fonctionnement et étude

Après une présentation de la technologie des Web Application Firewalls (ou pare-feu applicatifs), et de leurs enjeux, Mme Chou discutera des différents types de solutions WAF et des critères classiques d'évaluation de leurs performances. Cette présentation présentera les intérêts et limitations d'une telle solution, ainsi que l'écosystème dans lequel cette technologie s'inscrit.

Constance Chou est diplômée de Télécom SudParis (promotion 2021). Elle a suivi la VAP SSR et a reçu le titre ESSI de l'ANSSI. Elle a également obtenu le Prix Jeunes National André Blanc‐Lapierre, attribué par la Société de l'électricité, de l'électronique et des technologies de l'information et de la communication pour son stage de fin d’études effectué chez Thales SIX GTS France et intitulé : « Étude et intégration de pare-feu applicatifs ».

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Martin Spiering, Matthieu Touloucanon et Quentin Michaud (HackademINT) - 404 CTF

Plusieurs membres du club HackademINT présenteront leur retour sur l'organisation du 404 CTF, une compétition de sécurité qui s'est déroulée au printemps 2022, et qui était organisée par Télécom SudParis, en partenariat avec la DGSE et OVHcloud.

Martin Spiering présentera la mise en place de l'infra (kubernetes, rancher, docker...) en abordant les sécurités réseaux et les attaques (notamment bruteforce) subies pendant la compétition, ainsi que les mesures appliquées.

Matthieu Touloucanon insistera ensuite sur la sécurité système des Docker utilisés, notamment pour les challenges de la catégorie pwn (mais pas seulement), avec les bonnes pratiques Docker à suivre et l'utilisation de nsjail.

Enfin, Quentin Michaud présentera l'interface utilisée pour gérer la validation des challenges (CTFd), avec les modifications effectuées pour l'adapter à l'infrastructure du 404 CTF et supprimer un bug concernant s3. Ce sera l'occasion de discuter des avantages et inconvénients de l'open source qui découle de cette expérience.

MM. Spiering, Touloucanon et Michaud sont étudiants en 3e année à Télécom SudParis (promo 2023), actuellement en VAP SSR.

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Ministère de l'Intérieur - Analyse de flux chiffré en entreprise pour la détection d'incident de sécurité

Les communications en clair sur Internet et dans les environnements à hautes exigences de sécurité sont vouées à disparaître. L'adoption massive ces dernières années de l'utilisation par défaut des protocoles de chiffrement est en passe de devenir une quasi-exclusivité.

D'un autre point de vue, le chiffrement des flux constitue cependant un obstacle à la détection de comportements malveillants sur les systèmes d'information.

Après un rappel du fonctionnement de TLS, trois approches permettant l'analyse de flux chiffré seront présentées. Les enjeux et limitations seront discutés pour chacune des approches.

Amré Abouali (Cybershen) - Ancien RSSI & Entrepreneur

Amré Abouali est diplômé de Télécom SudParis (promotion 2017). Il a suivi la VAP SSR et a reçu le titre ESSI de l'ANSSI. Après avoir occupé deux postes de RSSI dans des environnements sensibles liés à la santé, il est aujourd'hui indépendant et entrepreneur dans le monde de la cybersécurité.

Olivier Levillain (TSP) - Influence de la qualité des spécifications sur la sécurité logicielle

Les systèmes d'information que nous utilisons quotidiennement sont d'une grande complexité. Ils reposent en particulier sur l'implémentation de protocoles réseau et sur l'interprétation de documents aux formats variés. Cette présentation traitera des spécifications décrivant ces protocoles et ces formats.

En particulier, il sera question de la manière dont ils sont spécifiés et des conséquences de cette manière sur la sécurité de leurs implémentations. Les exemples utilisés seront Mini-PNG, un format d'images utilisé dans un module d'enseignement en programmation, mais également le format PDF et le protocole TLS.

Olivier Levillain est maître de conférences en cybersécurité à Télécom SudParis.

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Rump Sessions

  • Constance Chou - Développement en cycle en V et IVVQ
  • Rémi Di Valentin et Yadi Huang - Offres IVVQ Cyber Thales
  • Ministère de l'Intérieur - Présentation d'une offre de stage de développement d'outil de sécurité pour le traitement de fichiers
  • Grégory Blanc et Olivier Levillain - Séminaire CoaP (Cybersecurity on a Plate / la cybersécurité sur un plateau)
  • Florian Martin - BlueTeam vs SMB
  • Romain Cherré - Filtrage et DNS : RPZ et XDP
  • Mathieu Degré - Introduction aux réseaux euclidiens (lattices)

Grégoire Menguy - Search-Based Local Blackbox Deobfuscation: Understand, Improve and Mitigate (October 4th 2022)

Publié le 04/10/2022
Par Olivier Levillain

Dans CoaP.

Pour cette première édition, nous recevons Grégoire Menguy, un ancien étudiant de Télécom SudParis, actuellement en thèse au CEA. Son intervention aura lieu à 14h dans le bâtiment IMT/TP/TSP, en salle 3.A405.

Les planches présentées sont disponible via ce lien

Search-Based Local Blackbox Deobfuscation: Understand, Improve and Mitigate

Code obfuscation aims at protecting Intellectual Property and other secrets embedded into software from being retrieved. Recent works leverage advances in artificial intelligence (AI) with the hope of getting blackbox deobfuscators completely immune to standard (whitebox) protection mechanisms. While promising, this new field of AI-based, and more specifically search-based blackbox deobfuscation, is still in its infancy. In this work, we deepen the state of search-based blackbox deobfuscation in three key directions: understand the current state-of-the-art, improve over it and design dedicated protection mechanisms. In particular, we define a novel generic framework for search-based blackbox deobfuscation encompassing prior work and highlighting key components; we are the first to point out that the search space underlying code deobfuscation is too unstable for simulation-based methods (e.g., Monte Carlo Tree Search used in prior work) and advocate the use of robust methods such as S-metaheuristics; we propose the new optimized search-based blackbox deobfuscator Xyntia which significantly outperforms prior work in terms of success rate (especially with small time budget) while being completely immune to the most recent anti-analysis code obfuscation methods; and finally we propose two novel protections against search-based blackbox deobfuscation, allowing to counter Xyntia powerful attacks.

This work has been published at CCS 2021.

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