Artificial Intelligence Security

Challenge: Understand the weaknesses of commercial and open-source machine learning malware detection models to targeted injections of bytes under threat of an adversary with only black-box query access.

Solution: An efficient binary-search that identified 2,048-byte windows whose alteration will reliably change detection model output labels from “malicious” to “benign.”

Result: A strong black-box attack and analysis method capable of probing vulnerabilities of malware detection systems, resulting in important insights toward robust feature selection for defenders and model developers.

Challenge: More accurately audit the privacy of machine learning systems while significantly reducing computational burden.

Solution: Novel attacks to efficiently reveal maximum possible information leakage and estimate privacy with higher statistical power and smaller sample sizes than previous state-of-the-art Monte Carlo sampling methods.

Result: A set of tools for creating dataset perturbations and performing hypothesis tests that allow developers of general machine learning systems to efficiently audit the privacy guarantees of their systems. 

Challenge: Quantify the risk associated with adversarial evasion attacks under a highly realistic threat model, which assumes adversaries have access to varying fractions of the model training data.

Solution: A comprehensive set of model training and testing experiments (e.g., more than 400 experiments on mini-ImageNet data) under differing mixtures of “private” and “public” data, as well as a novel attack that accounts for data class disparities by randomly dropping classes and averaging adversarial perturbations.

Result: Important and novel insights that, counterintuitively, conclude adversarial training can increase total risk under threat models for which adversaries have gray-box access to training data.