1. A computer-implemented method for identifying malicious servers, the computer-implemented method comprising: determining, by a computer, malicious edges between server vertices corresponding to visible servers and invisible servers involved in network traffic redirection chains based on determined graph-based features within a bipartite graph corresponding to visible and invisible server vertices involved in the network traffic redirection chains and determined distance-based features corresponding to the invisible server vertices involved in the network traffic redirection chains; identifying, by the computer, malicious server vertices in the bipartite graph based on the determined malicious edges between the server vertices corresponding to the visible servers and invisible servers involved in the network traffic redirection chains; and blocking, by the computer, access by client devices to malicious servers corresponding to the identified malicious server vertices in the bipartite graph.