Network attack detection at flow level

In this paper, we propose a new method for detecting unauthorized network intrusions, based on a traffic flow model and Cisco NetFlow protocol application. The method developed allows us not only to detect the most common types of network attack (DDoS and port scanning), but also to make a list of trespassers' IP-addresses. Therefore, this method can be applied in intrusion detection systems, and in those systems which lock these IP-addresses

No NAT'd User left Behind: Fingerprinting Users behind NAT from NetFlow Records alone

It is generally recognized that the traffic generated by an individual connected to a network acts as his biometric signature. Several tools exploit this fact to fingerprint and monitor users. Often, though, these tools assume to access the entire traffic, including IP addresses and payloads. This is not feasible on the grounds that both performance and privacy would be negatively affected. In reality, most ISPs convert user traffic into NetFlow records for a concise representation that does not include, for instance, any payloads. More importantly, large and distributed networks are usually NAT'd, thus a few IP addresses may be associated to thousands of users. We devised a new fingerprinting framework that overcomes these hurdles. Our system is able to analyze a huge amount of network traffic represented as NetFlows, with the intent to track people. It does so by accurately inferring when users are connected to the network and which IP addresses they are using, even though thousands of users are hidden behind NAT. Our prototype implementation was deployed and tested within an existing large metropolitan WiFi network serving about 200,000 users, with an average load of more than 1,000 users simultaneously connected behind 2 NAT'd IP addresses only. Our solution turned out to be very effective, with an accuracy greater than 90%. We also devised new tools and refined existing ones that may be applied to other contexts related to NetFlow analysis

Report of the Third Workshop on the Usage of NetFlow/IPFIX in Network Management

The Network Management Research Group (NMRG) organized in 2010 the Third Workshop on the Usage of NetFlow/IPFIX in Network Management, as part of the 78th IETF Meeting in Maastricht. Yearly organized since 2007, the workshop is an opportunity for people from both academia and industry to discuss the latest developments of the protocol, possibilities for new applications, and practical experiences. This report summarizes the presentations and the main conclusions of the workshop

Simpleweb/University of Twente Traffic Traces Data Repository

The computer networks research community lacks of shared measurement information. As a consequence, most researchers need to expend a considerable part of their time planning and executing measurements before being able to perform their studies. The lack of shared data also makes it hard to compare and validate results. This report describes our efforts to distribute a portion of our network data through the Simpleweb/University of Twente Traffic Traces Data Repository

NetFlow Data Manipulation Tool

Tato bakalářská práce se zabývá návrhem a implementací nástroje pro práci s daty NetFlow. Obsahuje teoretický rozbor způsobu monitorování sítě za pomocí IP Flow, popis nástroje nfdump a jeho způsob ukládání dat NetFlow v9. Při návrhu nástroje je kladen důraz na efektivní manipulaci s daty.This bachelor thesis deals with design and implementation of NetFlow data manipulation tool. It contains analysis of IP Flow network monitoring, description of nfdump tool and format of Netflow v9 records saved by nfdump. The focus of this work lies in effective manipulation with NetFlow records.