Abstract: A system and method for detecting malicious activity through one or more local analyzers and a central analyzer. The local analyzer captures packets that are part of communications over a network, generates a signature from information obtained from one or more of the captured packets, and determines whether the signature matches any signature of a first plurality of signatures stored in a first storage device that is accessible to the first local analyzer. The central analyzer remotely receives a portion of the information and the signature from the first local analyzer in response to the signature failing to match any of the signatures stored in the first storage device. The central analyzer determines whether the signature matches any global signature stored within a second storage device that is accessible to the central analyzer.

Abstract: Techniques may automatically detect bots or botnets running in a computer or other digital device by detecting command and control communications, called “call-backs,” from malicious code that has previously gained entry into the digital device. Callbacks are detected using a distributed approach employing one or more local analyzers and a central analyzer. The local analyzers capture packets of outbound communications, generate header signatures, and analyze the captured packets using various techniques. The techniques may include packet header signature matching against verified callback signatures, deep packet inspection. The central analyzer receives the header signatures and related header information from the local analyzers, may perform further analysis (for example, on-line host reputation analysis); determines using a heuristics analysis whether the signatures correspond to callbacks; and generally coordinates among the local analyzers.