WebVisor is an automatic tool to derive and detect patterns from malware Command and Control (C&C) server connections. From collective network communications stored on a large-scale malware dataset, WebVisor establishes the underlying patterns among samples of the same malware families. WebVisor focuses on C&C channels based on the Hypertext Transfer Protocol (HTTP). First, it builds clusters based on the structure and statistical features of the HTTP-based Uniform Resource Locators (URLs) stored in the malware dataset. Then, it conducts a fine-grained, noise-agnostic clustering process. Some more information is described in this paper.