SoK: Automated Software Diversity Per Larsen, Andrei Homescu, Stefan Brunthaler, Michael Franz University of California, Irvine

Abstract “...systematically study the state-of-the-art in software diversity and highlight fundamental trade-offs between fully automated approaches. We also point to open areas and unresolved challenges. These include “hybrid solutions”, error reporting, patching, and implementation disclosure attacks on diversified software.”

Taxonomy of Attacks Information Leaks Side Channel Attacks Memory Corruption Attacks Code Injection Code Reuse Just-In-Time Attacks Program Tampering Reverse Engineering

Taxonomy of Defenses Enforcement-based Defenses Program Integrity Monitors Diversity-based Defenses Program Obfuscation

What To Diversify Instruction Level Basic Block Level Loop Level Function Level Program Level System Level

When To Diversify Implementation Compilation and Linking Installation Loading Execution Updating

Security Impact Entropy – Higher Entropy means less chance of brute force attack being successful Attack specific code analysis Logical Arguments Testing against concrete attacks

Performance Impact

Unresolved Problems Hybrid Approaches Error Reports and Patches Implementation Disclosure Measuring Efficacy Diversity as a Counter to Side Channel Attacks

Conclusion Pre-distribution approaches are easy to implement, support the widest range of transformations, and can defense against client-side attacks Post-distribution support legacy and proprietary software, amortize diversification costs, and require no changes to current distribution mechanisms.