What Is Packet Sniffing in Cyber Security and How to Prevent It?

Last Updated: August 27, 2025

The world’s networks transmit billions of data packets every second, with each one bearing fragments of your emails, passwords, financial information, business secrets, and whatnot. That is an insane amount of online traffic, and the big question it raises is: How safe is your information?

Well, if recent reports are any indication, more than 60% of organizations have fallen victim to some sort of network monitoring or data packet interception within the past year alone. The tool behind most of these? Packet sniffing in cybersecurity.

Packet sniffing is a cyber tactic used to intercept and examine data packets in transit. While it serves as a tool of great significance for IT teams, it is also increasingly taken advantage of by cybercriminals, meaning to steal private data.

Understanding packet sniffing’s meaning and how you can defend against it is thus essential, especially in the digital world we live in. Let’s get into it, shall we?

What is Packet Sniffing in Cyber Security?

Packet sniffing in cybersecurity, put simply, is the act of capturing and analyzing data packets traveling through a network. Think of these packets as envelopes consisting of your personal information and carrying them from your device to their final, intended destination. A packet sniffer, as such, is a postal worker who discreetly opens and reads these envelopes as they go by.

Now that you know packet sniffing meaning, also note that it can be done for various reasons. While IT teams can use it for troubleshooting or performance monitoring, cybercriminals, conversely, can use it to steal sensitive information.

SentinelOne

4.2

Starting Price

Price on Request

How Does Packet Sniffing in Cyber Security Work?

Data that is sent through the internet gets divided into small packets. These packets house the information of the sender and the receiver, and the data itself. Normally, devices only process packets meant for them. However, a device running a network packet sniffer can capture all packets passing through its network segment.

Here’s how the process works…

  • Promiscuous Mode: The network adapter is configured to promiscuous mode, which enables it to receive all the traffic, not just that addressed to it.
  • Packet Interception: The traffic sniffer then collects data packets from the network, irrespective of what their destination.
  • Analysis: The captured packets are finally logged and analyzed using packet sniffing tools, which can reconstruct messages, reveal credentials, or expose private data.

This can be done both on wired networks (using an Ethernet packet sniffer or LAN packet sniffer) and wireless networks (using a WiFi sniffer).

What are the Different Types of Packet Sniffing in Cyber Security?

Packet sniffing in cyber security can be broken down into several distinct types, each with unique techniques and risks…

1. Passive Packet Sniffing

Passive packet sniffing is when the packet sniffer avoids interfering with any data but quietly monitors all network traffic. This works best on networks using hubs, where all devices see every packet.

2. Active Packet Sniffing

In this, the attacker adds extra traffic or tampers with network protocols (such as ARP spoofing) to cause switches to broadcast packets to all devices on the network. This allows the attacker to intercept data even on modern switched networks, which are typically designed to limit packet visibility to the intended recipient.

One example of active packet sniffing would be a hacker making use of ARP poisoning on a corporate LAN. This, to trick the switch into sending all traffic through their machine for interception.

Active packet sniffing is a common tactic in man-in-the-middle (MITM) attacks.

3. Filtered Packet Sniffing

The network packet sniffer, in filtered sniffing, is configured to intercept a particular type of packet, say, packets of a particular IP address, port, or protocol. This assists hackers in targeting sensitive information like login credentials or transactions.

4. Unfiltered Packet Sniffing

For unfiltered packet sniffing, on the contrary, the network packet sniffer picks up all packets without distinction, making a total record of the network traffic. Though data-intensive, this approach can produce unexpected outcomes when used in the process of forensic investigation.

Singularity Control

4.8

Starting Price

$ 79.99      

5. Protocol-Specific Sniffing

The traffic sniffer, in this case, targets only those network protocols that pass data in plain text or can be easily exploited. These include protocols like FTP, Telnet, HTTP, DNS, SMTP, etc. The best example of it would be the use of a Wi-Fi sniffer to intercept unencrypted FTP credentials at a public hotspot.

6. Application-Level Sniffing

The traffic sniffer is customized to target the data in particular applications, like email clients, browsers, or messaging apps, and reassemble entire conversations or document transfers. A LAN packet sniffer, for instance, can be used to reassemble chat messages sent using an internal messaging application over an unsecured network.

7. Hardware vs. Software Sniffers

Hardware sniffers are specialized devices connected to the network, which are commonly used by practitioners to perform in-depth diagnostics or by attackers to carry out covert long-term monitoring. Software sniffers, on the contrary, are applications such as Wireshark or tcpdump, which are installed on computers to capture and analyze packets.

Zaperon Zero Trust

4.1

Starting Price

Price on Request

8. LAN Sniffer vs. Wi-Fi Sniffer

While a LAN packet sniffer is used on wired networks to sniff traffic in a local area network, a Wi-Fi sniffer, on the other hand, is used on wireless networks to sniff information over the air. They are particularly dangerous when used over a public Wi-Fi, where encryption is sometimes lenient or non-existent.

How to Know If You Are Falling Victim to Packet Sniffing?

Detecting packet sniffing in cybersecurity is challenging because packet sniffing tools are designed to be stealthy. However, there are sundry warning signs and detection tactics that you can use to remain wary at all times. Some of them are mentioned below for your convenience…

  • Unusual Network Activity: Random slowdowns, unusual file transfers, or sudden data usage spikes are some of the key indicators of a network sniffing attack.
  • Frequent Disconnections: Active sniffing attacks sometimes disrupt normal network operations.
  • Security Software Alerts: Modern cybersecurity software can sometimes detect the presence of sniffers or alert you to suspicious devices on your network.
  • Manual Detection: Use sniffer detection tools like Aircrack, Wireshark, or specialized commercial products to scan for devices in promiscuous mode or for abnormal ARP traffic.
  • ARP Table Modifications: If your ARP tables are being altered without explanation, it may signal an active sniffing attempt using ARP spoofing.
  • Unexpected Devices: Unknown devices connected to your network, especially on public or business Wi-Fi, can be a red flag.

Prevention Techniques: Defending Against Packet Sniffing in Cyber Security

Packet sniffing in cybersecurity can be mitigated with a layered defence strategy. Here are the most effective methods you can use to attain the same…

  • Avoid Unsecured Networks: Public Wi-Fi is a prime target for attackers using WiFi sniffers. So, you should avoid connecting to unsecured networks, especially when transmitting sensitive data.
  • Use a VPN: A Virtual Private Network encrypts all your traffic, making intercepted packets unreadable to any packet sniffer or traffic sniffer on the same network.
  • Encrypted Protocols: Always use secure protocols such as HTTPS, SSL/TLS, SSH, and SFTP instead of their unencrypted counterparts. This is crucial for preventing password sniffing in cybersecurity.
  • Two-Factor Authentication: Even if credentials are intercepted, two-factor authentication adds an extra layer of security, making unauthorized access and password sniffing in cybersecurity much harder.
  • Disable Unnecessary Services & Ports: Close unused ports and disable unnecessary network services to reduce the attack surface for packet interception.
  • Use Strong Wi-Fi Security: Secure your wireless networks with WPA3 encryption and a strong, unique password. Avoid using outdated protocols like WEP.
  • Network Segmentation: Divide your network into smaller segments. If one segment is compromised, the rest remain protected.
  • Monitor & Scan Your Network: Use network monitoring tools and packet sniffing tools to watch for abnormal activity. Employ intrusion detection systems and regularly review logs for signs of sniffing attempts.
  • Employ Sniffer Detection Tools: Specialized tools can detect both passive and active sniffers on your network. These tools alert administrators to suspicious activity and help remove threats quickly.
  • Keep Systems Updated: Regularly update all devices, routers, and security software to patch vulnerabilities that sniffers might exploit.
  • Physical Security: Restrict physical access to network hardware. Prevent unauthorized devices from being plugged into your network, which could act as a hardware packet sniffer.

NeuShield Data Sentinel

4.3

Starting Price

Price on Request

Conclusion

Packet sniffing in cybersecurity is a constantly evolving threat. Attackers today make use of a variety of sniffing techniques to intercept and analyze network traffic. Things definitely get riskier when unsecured or public networks are involved, but even private networks can become dangerous if used without proper defences.

Understanding what packet sniffing is and how these attacks work is thus the first step in defending yourself. So, stay alert for signs of trouble, use encryption, and let a good cybersecurity software guide the way for you. Call the Techjockey product team today if you need any help with the lattermost.

Published On: August 27, 2025
Yashika Aneja

Yashika Aneja is a Senior Content Writer at Techjockey, with over 5 years of experience in content creation and management. From writing about normal everyday affairs to profound fact-based stories on wide-ranging themes, including environment, technology, education, politics, social media, travel, lifestyle so on and so forth, she has, as part of her professional journey so far, shown acute proficiency in almost all sorts of genres/formats/styles of writing. With perpetual curiosity and enthusiasm to delve into the new and the uncharted, she is thusly always at the top of her lexical game, one priceless word at a time.

Share
Published by
Yashika Aneja

Recent Posts

Watering Hole Attack – How It Works and How to Prevent It?

Are your business-critical sites really safe? What if attackers could breach your network without targeting… Read More

August 26, 2025

Why Your Logistics Business Needs Yard Management System?

Have you ever had a truck sit out at your facility for hours just because… Read More

August 26, 2025

SEO vs GEO vs AEO: Let’s Clear the Confusion

It’s been years since SEO has been the cornerstone of digital visibility. Not only in… Read More

August 26, 2025

Top 10 ITR Filing Mistakes People Make During Tax Season

You might think filing an Income Tax Return (ITR) is simple process using any… Read More

August 24, 2025

How Brands Use AI for Customer Engagement?

With attention spans getting shorter by the minute, brands and businesses are finding it increasingly… Read More

August 23, 2025

Perplexity Comet vs Google Chrome: Is AI Ready to Replace Traditional Browsers?

In the last five years, since 2018, Chrome has seen significant rise in its… Read More

August 21, 2025