Zeroth-order optimization is an important research topic in machine learning.
In recent years, it has become a key tool in black-box adversarial attack to
neural network based image classifiers. However, existing zeroth-order
optimization algorithms rarely extract second-order information of the model
function. In this paper, we utilize the second-order information of the
objective function and propose a novel \textit{Hessian-aware zeroth-order
algorithm} called \texttt{ZO-HessAware}. Our theoretical result shows that
\texttt{ZO-HessAware} has an improved zeroth-order convergence rate and query
complexity under structured Hessian approximation, where we propose a few
approximation methods for estimating Hessian. Our empirical studies on the
black-box adversarial attack problem validate that our algorithm can achieve
improved success rates with a lower query complexity.