Saeid Tizpaz-Niari (University of Colorado Boulder), Pavol Černý (TU Wien), Ashutosh Trivedi (University of Colorado Boulder)

Information leaks through side channels are a pervasive problem, even in security-critical applications. Functional side channels arise when an attacker knows that a secret value of a server stays fixed for a certain time. Then, the attacker can observe the server executions on a sequence of different public inputs, each paired with the same secret input. Thus for each
secret, the attacker observes a (partial) function from public inputs to execution time, for instance, and she can compare these functions for different secrets.

First, we introduce a notion of noninterference for functional side channels. We focus on the case of noisy observations, where we demonstrate with examples that there is a practical functional
side channel in programs that would be deemed information-leak-free or be underestimated using the standard definition. Second, we develop a framework and techniques for debugging programs for functional side channels. We extend evolutionary fuzzing techniques to generate inputs that exploit functional dependencies of response times on public inputs. We adapt existing results and algorithms in functional data analysis (such as functional clustering) to model the functions and discover the existence of side channels. We use a functional extension of standard
decision tree learning to pinpoint the code fragments causing a side channel if there is one.

We empirically evaluate the performance of our tool FUCHSIA on a series of micro-benchmarks, as well as on realistic Java programs. On the set of micro-benchmark, we show that FUCHSIA
outperforms the state-of-the-art techniques in detecting side channel classes. On the realistic programs, we show the scalability of FUCHSIA in analyzing functional side channels in Java programs with thousands of methods. In addition, we show the usefulness of FUCHSIA in finding (and locating in code) side channels including a zero-day vulnerability in Open Java Development Kit and another Java web server vulnerability that was since fixed by the original developers.

View More Papers

Dynamic Searchable Encryption with Small Client Storage

Ioannis Demertzis (University of Maryland), Javad Ghareh Chamani (Hong Kong University of Science and Technology & Sharif University of Technology), Dimitrios Papadopoulos (Hong Kong University of Science and Technology), Charalampos Papamanthou (University of Maryland)

Read More

Unicorn: Runtime Provenance-Based Detector for Advanced Persistent Threats

Xueyuan Han (Harvard University), Thomas Pasquier (University of Bristol), Adam Bates (University of Illinois at Urbana-Champaign), James Mickens (Harvard University), Margo Seltzer (University of British Columbia)

Read More

Proof of Storage-Time: Efficiently Checking Continuous Data Availability

Giuseppe Ateniese (Stevens Institute of Technology), Long Chen (New Jersey Institute of Technology), Mohammard Etemad (Stevens Institute of Technology), Qiang Tang (New Jersey Institute of Technology)

Read More

Revisiting Leakage Abuse Attacks

Laura Blackstone (Brown University), Seny Kamara (Brown University), Tarik Moataz (Brown University)

Read More