Analyzing network flow records
Go with the Flow
© Lead Image © Artur Szydlowski, 123RF.com
Detect operating systems, installed software, and more from easily collected metadata.
What operating systems are installed on your network, and what software is running on them? Questions like these are often posed in IT departments – especially if users are operating their own shadow IT [1] or when documentation, automation, and software distribution need some care and attention. However, you have good reasons to ask these questions: Attackers are also interested in your systems.
Many methods of discovering the current status quo have been developed in recent years; they rely on either actively measuring [2] (e.g., with Nmap) or passively sniffing network traffic [3]. The passive method analyzes all or parts of your network traffic, from which you can draw conclusions. For example, a device that regularly visits the IP address for the domain name update.microsoft.com would lead to the conclusion that the operating system comes from Microsoft.
In this article, we present a new approach based on network traffic analysis that exclusively considers the widespread and often easily available network communication metadata in the form of flow records. Metadata analysis of network connections can offer many benefits: It requires far less memory and computational power than the analysis of complete packets, it is compliant with data protection, and it does not need port mirroring on the router; moreover, it is comparatively fast.
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