Collecting and Analyzing NetFlow for Incident Response

Collecting and analyzing NetFlow for incident response

As with any type of cybersecurity incident, you can only respond against a threat if you are able to detect it in the first place. As you can imagine, detecting potential threats or security incidents in a large and complex network, filled with a diverse lineup of end-devices, routers, and lines of communication presents a major challenge to security teams. Netflow is one incident response tool that can allow security experts to efficiently detect possible network intrusions and threats,, so that incident response can be engaged to mitigate the potential damage ASAP.

While NetFlow may help you accelerate your incident response, you will still need an incident response plan to effectively deal with these situations and mitigate the harm.


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What is NetFlow?

The NetFlow name is somewhat explanatory. It’s a network protocol developed by Cisco that collects and analyzes the flow of network IP traffic through your network interfaces, such as routers, switches, and other edge devices. It provides full, time-stamped visibility regarding all the information in and out of your network, including important characteristics, such as point of origin, destination, volume, and the path it travelled throughout your network.

NetFlow was invented as an improvement of SNMP (Simple Network Management Protocol) which was previously prevalently used by network engineers and administrators. NetFlow has emerged as the de facto standard in network traffic monitoring, supported and implemented widely by almost all major network equipment vendors.

How Does NetFlow Work?

As you may have surmised, the main tasks of NetFlow are to collect, organize, and analyze network traffic data. NetFlow consists of a number of main components that enables it to achieve this goal:

  • IP Flow: This term refers to a group of IP packets with the same attributes, such as IP and destination address, protocol type, etc. This information is collected when a packet passes through a router or switch and used to identify related traffic.
  • NetFlow Cache: This is basically a database of all the network traffic information collected and sorted by NetFlow.
  • Command Line Interface: This is the main method which administrators can use to access, configure, and troubleshoot NetFlow.
  • NetFlow Collector: This is a reporting server (hardware or software-based) that NetFlow users can configure to export NetFlow data to for processing.

Using these components, NetFlow is able to scan your network for possible security incidents. It does this by looking for typical markers of a network attack. For example, a DDoS (Distributed Denial of Service) attack is one of the most common faced by business networks. If NetFlow detects a suspiciously large number of packets coming from the same external source within a short timeframe, it’s a possible indication a DDoS attack is taking place.

Why Should You Use NetFlow for Incident Response?

Just like any cybersecurity incident, reducing metrics such as MTTD (Mean Time to Detect) and MTTR (Mean Time to Respond) are crucial to mitigating the potential damage and restoring normal operations as soon as possible. For many organizations, their network IS the business, and an attack, e.g.DDOS attack, can leave them unable to service customers or carry out day-to-day business operations.

The main purpose in implementing NetFlow then is to dramatically shorten the time it takes to detect potential attacks so that you can start the incident response process. This can be done in a number of ways:

  • Network Monitoring: Security or network operators can actively monitor network data for any discrepancies. This can involve anything from suspiciously addressed packages to unexpected traffic flows/volumes to users violating security or usage policies.
  • Network Planning: Not only can NetFlow help to identify vulnerable assets and shore up security where it’s needed, but it will also enable better network planning. Inefficiencies, misconfigurations, or overloaded network assets are just as likely to cause damaging disruptions as malicious attacks.
  • Security Analysis: With NetFlow, security and network teams will have a highly detailed flow of real-time information as well as an audit trail of network flow and incidents with an as-it-happened breakdown of events. NetFlow can be used as an anomaly detection tool that should aid in being able to identify active and past incidents in shorter time frames.

Are you ready to deal with security threats to your network?

For many businesses today, the answer is still no. Traditional methods of threat detection and prevention are no longer capable of handling modern day networks with its rapidly growing traffic volumes, diverse interfaces, and number of threats. Using NetFlow as an incident response tool can help you recover from attacks and anomalous behavior faster by providing quick and actionable insights into traffic behavior on your network. Combined with an effective incident response plan, it can play a huge role in limiting the vulnerability of your networks and assets.



NetFlow for Cybersecurity

What Is NetFlow? How NetFlow Works and Why to Use It