What are packet sniffing and traffic sniffing?

Anton P. | October 16, 2023

Packet sniffing and traffic sniffing are two related concepts that people sometimes use interchangeably. However, traffic sniffing refers to all-encompassing network traffic analysis. Meanwhile, packet sniffing concentrates on individual data packets.

Packet sniffing attacks are cybersecurity threats that can hurt companies and private users alike. This article will shed light on how VPNs and other solutions can help protect against these threats.

Traffic sniffing refers to high-level analysis of network traffic, while packet sniffing is one of its main methods

What is packet sniffing?

Packet sniffing, or packet capture, entails capturing individual network data packets. These packets contain information like source and destination IP addresses, transmission control protocol details, and the actual data transmitted.

Packet sniffing gathers, logs, and analyzes these data units. A tool called packet sniffer does it with either some or all the packets that travel across the network.

Packet sniffer

A packet sniffer or packet analyzer is any tool that does the actual packet sniffing. There are two main types of packet sniffers.

  • A hardware packet sniffing tool is a separate device that plugs into the network. Hardware packet sniffer then uses software programs to capture and analyze packets.
  • A software packet sniffing tool does not use a physical entry point and connects to the network virtually. It is a software application capable of collecting data packets and logging and analyzing information.

Two main components comprise both types of packet sniffers:

  1. A network adapter that connects the sniffing tool to the network.
  2. Software program that creates a way to monitor or log the data in the network packets.

Large network administrators might combine multiple hardware and software sniffers to capture all the data effectively.

How does it relate to traffic sniffing?

Traffic sniffing refers to the practice of monitoring and analyzing network traffic as a whole. Rather than concentrating on individual packets, traffic sniffing aims to extract broader insights about the overall network activity.

Thus, traffic sniffing might involve high-level network analysis over a long period. Administrators and network security experts might look at session data, connectivity patterns, and behaviors within the network.

This kind of traffic sniffing allows for identifying security threats, network congestion risks, and other areas of improvement.

Packet sniffing is one of the most important ways the administrator monitors network traffic. Thus, it is an essential subset of traffic sniffing. Some administrators might even refer to traffic sniffing exclusively as packet sniffing.

In cyber security research, we also usually talk about packet sniffing attacks. This is because hackers often target individual data packets to hack the network.

Private Christmas & a safe New Year!


What is a packet sniffing attack?

Unlike authorized personnel, hackers use packet sniffing for malicious purposes. A packet sniffing attack is when unauthorized agents breach network security and intercept data packets.

Hackers also use packet sniffing tools for these attacks. The main packet sniffer types also provide two distinct ways to initiate sniffing attacks:

  • On-premises connection. Hackers might connect a device to the local area network (LAN) by finding an access point. The malicious actor might have legitimate access to the network but lack authorization to deploy a sniffing tool. Organizations encounter insider attacks of this type more commonly than believed. 
  • Wireless connection. Malicious agents might target unsafe public Wi-Fi. By deploying software sniffers, hackers might monitor all internet traffic passing through the network. If there are no additional protections, hackers can monitor data packets from remote networks.

Traffic sniffing attacks also have two models based on whether the attacker further acts on the network.

Active sniffing attacks

Active sniffing attacks involve hackers using the packet interception to further tamper with the network. For example, they can add malicious code to the packet data, disrupting or shutting down network traffic completely.

An insider can use address resolution protocol (ARP) spoofing, which involves sending fake ARP messages to other network devices. These devices will then send to the hacker data packets meant for network switches or routers.

With this type of man-in-the-middle (MitM) attack, the insider can access more sensitive information than permitted.

Passive sniffing attacks

Passive traffic sniffing attacks do not require adding new traffic to the network. The hacker only positions themselves to monitor and log network traffic.

This attack allows the stealing of personal information that can later be sold or used for other malicious purposes. Since the hacker makes no changes to network traffic, passive attacks are tough to detect.

How to protect your network from sniffing attacks?

Traffic sniffing and packet sniffing can cause severe damage to the network users when done by hostile agents. In order to protect your network from sniffing attacks, take the following precautions. 

  • Use VPNs.  Mandating VPN connections for all network devices can significantly reduce the risk of sniffing attacks. Especially when remote users connect from public networks. VPNs will encrypt all network traffic, allowing potential interceptors only to see the encrypted packets.
  • Segment the network. Use multiple routers and network switches to divide your network. This will help protect extra sensitive data and contain sniffing attacks. If hackers attempt to access all network traffic, they must take active steps. Security systems are better able to detect such steps than passive monitoring.
  • Use robust authentication methods. Strong passwords, multi-factor authentication, and robust network access control (NAC) policies help protect from unauthorized connections.
  • Regularly update your software. Make sure you use the latest version of all your network tools. Always look for bugs and issues across your systems to fix them before attackers can exploit them.
  • Disable unnecessary applications and services. Reduce the attack surface by turning off all unnecessary services. Disable applications and protocols that might be vulnerable to sniffing attacks.
  • Limit physical access to your network. Enforce strict policies regarding who can physically be around your network devices. Watch out for tailgating and suspicious activities around your hardware.

All network users should practice these pillars of cybersecurity. Thus, make sure to organize adequate training. Hackers will have a very hard time with traffic sniffing if everyone does their part in protecting the network.

Anton P.

Anton P.

Former chef and the head of Atlas VPN blog team. He's an experienced cybersecurity expert with a background of technical content writing.


Privacynetwork securitycyber threatsattacks

© 2023 Atlas VPN. All rights reserved.