Bart Coppens — Research

myself in the Swiss alps

I'm a part-time assistant professor of system and software security and post-doctoral researcher at Ghent University (UGent), ELIS Department, Computer Systems Lab. This is my research-related page, I also have a personal homepage. From 2003 to 2007 I worked on my Master's degree in Computer Science (a 'licentiaat in de informatica'), and in June 2013 I received my PhD in Computer Science Engineering.

My research interests are multi-variant execution environments, program analyses for finding security issues in low-level code, timing-based side-channel attacks, software obfuscations, software diversity, and software security and systems security in general.


My research is about automatically making binary programs more secure (given different attack models). For example, I have worked on the compiler-level generation of binary code to output programs that are less vulnerable to timing-based side channel attacks, and on rewriting binary code at link-time to make it more resistant against patch-based attacks. I have also worked on other techniques to protect software against different types of attacks: Multi-Variant Execution Environments (MVEEs) to protect software against exploits, on finding security vulnerabilities in operating systems (such as Linux), anti-debugging techniques to delay some forms of reverse engineering, etc.

Multi-Variant Execution. Legacy code bases written in an unsafe language, will contain vulnerabilities which can be exploited in different ways. Multi-Variant Execution allows mitigating and preventing entire classes of exploits for these vulnerabilities. A monitor executes the same program multiple times (in parallel) on the same input. Rather than run these programs in an identical fashion, the multi-variant execution environment enforces structural diversity between the variants. This diversity is constructed in such a way that under normal inputs, all variants behave identically; but when an attacker feeds malicious inputs to the program, the behavior of the variants diverges. The monitor detects this divergence, and halts the execution before malicious system calls are executed. Making multi-variant execution environments support larger classes of programs while keeping the overhead small is an active research topic. In our group we work on improving the ReMon Multi-Variant Execution Environment.

Protection against patch-based attacks. The problem of patch-based attacks is that of Patch Tuesday/Exploit Wednesday. Here a security update is released, after which hackers try to find the vulnerability in the unpatched program by analyzing the difference between the original version of the program and the patched version. If this can be done fast enough, attackers can exploit this vulnerability with the mass of users that has not yet applied this patch. Applying software diversity increases the effort for attacker to find the original vulnerability, thus increasing the time window in which a user running unpatched code is safe from such exploitation. I try to mitigate these using software diversity. This is a technique where an application instance is transformed into syntactically different, but semantically equivalent instance. I do this at link time using the binary link time rewriting framework Diablo.

The first step is to evaluate the effectiveness of diversification strategies in slowing down an attacker. Assuming that an attacker will use existing tools to pinpoint the changes in the code, I compared different binary diffing tools and studied different ways in which they can be used to measure the effectiveness of existing diversification strategies.

I then improved the existing diversification techniques in order to deliver a similar slow-down for the attacker, but with a lower overhead in execution time of the patched program. This is done by using the binary diffing tools to compare which code fragments are still matched, and using this information in a feedback loop to iteratively transform only code that is still matched. I worked for the Aspire FP7 project, in which I've extended these techniques.

Protection against side-channel attacks. Differences in the execution time of a program can give an attacker additional information on the internal state of a cryptographic algorithm, potentially leading to the compromise of secret information. I researched mitigating side-channels on modern x86 processors. I worked on a compiler-based toolflow to apply if-conversion to cryptographical code in order to eliminate control-flow related side-channels. Furthermore, using the division instruction as an example of a variable-latency instruction on the x86 architecture, I evaluated different techniques to mitigate data-flow related timing side-channels.

Multi-Variant Execution Environments
  1. Sharing is Caring: Secure and Efficient Shared Memory Support for MVEEs [Code]
    Jonas Vinck, Bert Abrath, Bart Coppens, Alexios Voulimeneas, Bjorn De Sutter, Stijn Volckaert
    EuroSys, 2022
  2. Multi-Variant Execution
    Bart Coppens, Bjorn De Sutter, Stijn Volckaert
    Book chapter, 'The Continuing Arms Race: Code-Reuse Attacks and Defences', ACM Books / Morgan & Claypool Publishers, 2018
  3. Taming Parallelism in a Multi-Variant Execution Environment [Code]
    Stijn Volckaert, Bart Coppens, Bjorn De Sutter, Koen De Bosschere, Per Larsen, Michael Franz
    EuroSys, 2017
  4. Secure and Efficient Application Monitoring and Replication [Code]
    Stijn Volckaert, Bart Coppens, Alexios Voulimeneas, Andrei Homescu, Per Larsen, Bjorn De Sutter, Michael Franz
    USENIX Annual Technical Conference (ATC), 2016
  5. Cloning your Gadgets: Complete ROP Attack Immunity with Multi-Variant Execution [Code]
    Stijn Volckaert, Bart Coppens, Bjorn De Sutter
    IEEE Transactions on Dependable and Secure Computing (TDSC), 2016
Software security
  1. ApkDiff: Matching Android App Versions Based on Class Structure
    Robbe De Ghein, Bert Abrath, Bjorn De Sutter, Bart Coppens
    to appear at CheckMATE, 2022
  2. Flexible Software Protection [Code]
    Jens Van den Broeck, Bart Coppens, Bjorn De Sutter
    Computers & Security, 2022
  3. Obfuscated Integration of Software Protections [Code]
    Jens Van den Broeck, Bart Coppens, Bjorn De Sutter
    International Journal of Information Security, 2021
  4. Resilient Self-Debugging Software Protection [Code]
    Bert Abrath, Bart Coppens, Ilja Nevolin, Bjorn De Sutter
    Workshop on Software Attacks and Defenses (SAD), 2020
  5. Code Renewability for Native Software Protection [Code]
    Bert Abrath, Bart Coppens, Jens Van den Broeck, Brecht Wyseur, Alessandro Cabutto, Paolo Falcarin, Bjorn De Sutter
    ACM Transactions on Privacy and Security, 2020
  6. ΔBreakpad: Diversified Binary Crash Reporting [Code]
    Bert Abrath, Bart Coppens, Mohit Mishra, Jens Van den Broeck, Bjorn De Sutter
    IEEE Transactions on Dependable and Secure Computing (TDSC), 2020
  7. Understanding the Behaviour of Hackers while Performing Attack Tasks in a Professional Setting and in a Public Challenge
    Mariano Ceccato, Paolo Tonella, Cataldo Basile, Paolo Falcarin, Marco Torchiano, Bart Coppens, Bjorn De Sutter
    Empirical Software Engineering (EMSE), 2019
  8. How Professional Hackers Understand Protected Code while Performing Attack Tasks
    Mariano Ceccato, Paolo Tonella, Aldo Basile, Bart Coppens, Bjorn De Sutter, Paolo Falcarin, Marco Torchiano
    International Conference on Program Comprehension (ICPC), 2017
  9. Tightly-coupled self-debugging software protection [Code]
    Bert Abrath, Bart Coppens, Stijn Volckaert, Joris Wijnant, Bjorn De Sutter
    Workshop on Software Security, Protection, and Reverse Engineering (SSPREW), 2016
  10. Reactive Attestation: Automatic Detection and Reaction to Software Tampering Attacks [Remote attestation code]
    Alessio Viticchié, Cataldo Basile, Andrea Avancini, Mariano Ceccato, Bert Abrath, Bart Coppens
    International Workshop on Software Protection (SPRO), 2016
  11. SOFIA: Software and control flow integrity architecture
    Ruan de Clercq, Ronald De Keulenaer, Bart Coppens, Bohan Yang, Pieter Maene, Koen De Bosschere, Bart Preneel, Bjorn De Sutter, Ingrid Verbauwhede
    Design, Automation and Test in Europe (DATE), 2016
  12. Obfuscating Windows DLLs
    Bert Abrath, Bart Coppens, Stijn Volckaert, Bjorn De Sutter
    International Workshop on Software Protection (SPRO), 2015
  13. Software Protection with Code Mobility [Code]
    Alessandro Cabutto, Paolo Falcarin, Bert Abrath, Bart Coppens, Bjorn De Sutter
    Workshop on Moving Target Defense (MTD), 2016
  14. Program Variation for Software Security
    Bart Coppens
    PhD thesis, Ghent University, 2013
  15. Feedback-driven binary code diversification [Code]
    Bart Coppens, Bjorn De Sutter, Jonas Maebe
    ACM Transactions on Architecture and Code Optimization (TACO), 2013
  16. Protecting Your Software Updates
    Bart Coppens, Bjorn De Sutter, Koen De Bosschere
    IEEE Security & Privacy magazine, 2013
  17. A Novel Obfuscation: Class Hierarchy Flattening
    Christophe Foket, Bjorn De Sutter, Bart Coppens, and Koen De Bosschere
    International Symposium on Foundations & Practice of Security (FPS), 2012
  18. DNS Tunneling for Network Penetration [Code]
    Daan Raman, Bjorn De Sutter, Bart Coppens, Stijn Volckaert, Koen De Bosschere, Pieter Danhieux, Erik Van Buggenhout
    International Conference on Information Security and Cryptology (ICISC), 2012
  19. Compiler mitigations for time attacks on modern x86 processors
    Jeroen Van Cleemput, Bart Coppens, Bjorn De Sutter
    ACM Transactions on Architecture and Code Optimization (TACO), 2012
  20. Practical Mitigations for Timing-Based Side-Channel Attacks on Modern x86 Processors
    Bart Coppens, Ingrid Verbauwhede, Koen De Bosschere and Bjorn De Sutter
    IEEE Symposium on Security and Privacy (Oakland, S&P), 2009
Boundaries of patches (Master's thesis research)
  1. An Efficient Algorithm for the Generation of Planar Polycyclic Hydrocarbons with a Given Boundary [Code integrated in CaGe]
    Gunnar Brinkmann and Bart Coppens
    MATCH Communications in Mathematical and in Computer Chemistry, 2008
  2. Grenzen van Patches [Code]
    Bart Coppens
    Master's Thesis in Computer Science ('Licentiaat Informatica') (Dutch), 2007
  1. HiPEAC Vision 2021
    Editorial Board: Marc Duranton, Koen De Bosschere, Bart Coppens, Christian Gamrat, Thomas Hoberg, Harm Munk, Catherine Roderick, Tullio Vardanega, Olivier Zendra
    HiPEAC, 2021
  2. HiPEAC Vision 2019
    Editorial Board: Marc Duranton, Koen De Bosschere, Bart Coppens, Christian Gamrat, Madeleine Gray, Harm Munk, Emre Ozer, Tullio Vardanega, Olivier Zendra
    HiPEAC, 2019

I am a co-lecturer of the following courses:

Computer Labs

I currently assist in the (computer) labs of the following courses:

  • Computerarchitectuur, an introductory course on computer architecture.
  • Besturingssystemen, an introductory course on operating systems (with labs to set up virtual memory on the Raspberry Pi 4B).


My personal email address is kde @

My university email address is Bart.Coppens @

My PGP key fingerprint is 1540 BAC4 779C EACB 5212 A959 6516 95B0 5F29 CF10 (also available on

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