Sniffers

What Is a Sniffer?

A sniffer is a tool that can intercept and log Internet traffic. It can be either software or hardware-based, and it has many other names, including packet analyzer, packet sniffer, or protocol analyzer. The reason it is called a packet analyzer is that a packet is a unit of data that is carried between networks and machines through traffic. So, a sniffer to varying degrees can capture and analyze the packets that flow within the data streams, depending on what the tool is capable of.

Sniffer’s modifications and capabilities depend on what kind of traffic it logs. It is possible to capture traffic on shared medium networks, modern networks, wireless LANs, and so on. Thus, there are several ways to configure sniffers. If the tool is powerful enough to capture all traffic on the monitored network, the sniffer can work in unfiltered mode, where it collects all data packets and stores them on a designated hard drive. Later, a specialist goes through the stored data. If the network traffic is too big to capture all of it, sniffers can be modified to filter certain traffic so that they could capture only particular data that is deemed to be necessary.

The mode of operation for a sniffer may also differ depending on whether it monitors a wired or a wireless network. Wired networks can have network switches that can limit sniffers’ access to the data packets. On a wireless network, sniffers can usually go through one channel at a time. This capability can be expanded, but then it would require multiple wireless interfaces.

What Are Sniffers Used For?

For the most part, sniffers are used to analyze and detect network problems. They can be used to check networks for potential intrusion attempts or to document regulatory compliance by logging endpoint traffic. Since it is a tool for network analysis, it can be used for a variety of things, from collecting network statistics to isolating exploited systems. All in all, when sniffers are used by professional IT teams, they can improve network performance and efficiency. But we would not be writing about this tool if it could not be used for malicious purposes, too.

What Are the Sniffer-Related Risks?

Since sniffers can capture almost any traffic, they can be used for surveillance not only by the companies that want to regular their own traffic but also by cybercriminals. Malicious sniffers could easily enter the targeted network if one user opens a spam email attachment or an infected file on a website that is used for malware distribution. A malicious sniffer can collect and log traffic data to later send it over to its command and control server.

While sniffers themselves cannot cause direct damage to the system, they can be used as reconnaissance tools. Consequently, they could lead to man-in-the-middle or even ransomware attacks, and so, it is important to maintain a healthy network environment to avoid such potential threats. Proper staff training and a professional IT team can help with that, but investing in a powerful anti-malware solution is also vital.