Bio:

Oussama Draissi is a research assistant at the System Security group. His research focuses on developing protective mechanisms and analyzing vulnerabilities in applications across various platforms, including the browser, smart contracts, and RISC-V.

Curriculum Vitae:

since 06/2022

Research assistant at the Secure Systems group at the University of Duisburg-Essen

06/2019 - 05/2022

Scientific assistant at the Secure Systems group at the University of Duisburg-Essen

10/2019 - 03/2022

Master of Science in Software and Network Engineering at the University of Duisburg-Essen

12/2017 - 05/2019

Student Assistant at the Secure Systems group at the University of Duisburg-Essen

04/2015 - 05/2019

Bachelor of Science in Applied Computer Science - Systems Engineering at the University of Duisburg-Essen

Bachelor's thesis: Evaluation of Automated Advanced Information Leak Exploitation for Memory Corruption Attacks    

Publications:

• Draissi, Oussama; Cloosters, Tobias; Klein, David; Rodler, Michael; Musch, Marius; Johns, Martin; Davi, Lucas: Wemby's Web: Hunting for Memory Corruption in WebAssembly. In: Proc. of the 34th International Symposium on Software Testing and Analysis (ISSTA). ACM, Trondheim, Norway 2025. CitationAbstractDetails

  WebAssembly enables fast execution of performance-critical in web applications utilizing native code.
  However, recent research has demonstrated the potential for memory corruption errors within WebAssembly modules to exploit web applications.
  In this work, we present the first systematic analysis of memory corruption in WebAssembly, unveiling the prevalence of a novel threat model where memory corruption enables code injection on a victim’s browser.
  Our large-scale analysis across 37 797 domains reveals that an alarming 29 411 (77.81 %) of those fully trust data coming from potentially attacker-controlled sources.
  As a result, an attacker can exploit memory errors to manipulate the WebAssembly memory, where the data is implicitly trusted and frequently passed into security-sensitive functions such as eval or directly into the DOM via innerHTML.
  Thus, an attacker can abuse this trust to gain JavaScript code execution, i.e., Cross-Site Scripting (XSS).

  To tackle this issue, we present Wemby, the first viable approach to efficiently analyze WebAssembly-powered websites holistically.
  We demonstrate that Wemby is proficient at detecting remotely exposed memory corruption errors in web applications through fuzzing.
  For this purpose, we implement binary-only WebAssembly instrumentation that provides fine-grained memory corruption oracles.
  We applied Wemby to different websites, uncovering several security-critical functions and memory corruption bugs, including one on the Zoom platform.
  In terms of performance, our ablation study demonstrates that Wemby outperforms cuurent WebAssembly fuzzers.
  Specifically, Wemby achieves an average speed improvement of 232 times and delivers 46% greater code coverage compared to the state-of-the-art.

• Cloosters, Tobias; Draissi, Oussama; Willbold, Johannes; Holz, Thorsten; Davi, Lucas: Memory Corruption at the Border of Trusted Execution. In: IEEE Security & Privacy, Vol 2024 (2024), p. 2-11. doi:10.1109/MSEC.2024.3381439CitationAbstractDetails

  Trusted execution environments provide strong security guarantees, like isolation and confidentiality, but are not immune from memory-safety violations. Our investigation of public trusted execution environment code based on symbolic execution and fuzzing reveals subtle memory safety issues.

• Smolka, Sven; Giesen, Jens-Rene; Winkler, Pascal; Draissi, Oussama; Davi, Lucas; Karame, Ghassan; Pohl, Klaus: Fuzz on the Beach: Fuzzing Solana Smart Contracts. In: Proc. of the 30th ACM SIGSAC Conference on Computer & Communications Security (CCS). ACM, Copenhagen, Denmark 2023. CitationAbstractDetails

  Solana has quickly emerged as a popular platform for building decentralized applications (DApps), such as marketplaces for non- fungible tokens (NFTs). A key reason for its success are Solana’s low transaction fees and high performance, which is achieved in part due to its stateless programming model. Although the litera- ture features extensive tooling support for smart contract security, current solutions are largely tailored for the Ethereum Virtual Ma- chine. Unfortunately, the very stateless nature of Solana’s execution environment introduces novel attack patterns specific to Solana requiring a rethinking for building vulnerability analysis methods. In this paper, we address this gap and propose FuzzDelSol, the first binary-only coverage-guided fuzzing architecture for Solana smart contracts. FuzzDelSol faithfully models runtime specifics such as smart contract interactions. Moreover, since source code is not available for the large majority of Solana contracts, FuzzDelSol operates on the contract’s binary code. Hence, due to the lack of semantic information, we carefully extracted low-level program and state information to develop a diverse set of bug oracles covering all major bug classes in Solana. Our extensive evaluation on 6049 smart contracts shows that FuzzDelSol’s bug oracles finds impactful vulnerabilities with a high precision and recall. To the best of our knowledge, this is the largest evaluation of the security landscape on the Solana mainnet.

• Cloosters, Tobias; Paaßen, David; Wang, Jianqiang; Draissi, Oussama; Jauernig, Patrick; Stapf, Emmanuel; Davi, Lucas; Sadeghi, Ahmad-Reza: RiscyROP: Automated Return-Oriented Programming Attacks on RISC-V and ARM64. In: Proc. of the 25th International Symposium on Research in Attacks, Intrusions and Defenses (RAID 2022). Limassol, Cyprus 2022. doi:10.1145/3545948.3545997PDFCitationDetails