What Are Packet Sniffers and How Do They Work? (2024)

Packet sniffers or protocol analyzers are tools used by network technicians to diagnose network-related problems. Hackers use packet sniffers for less noble purposes, such as spying on network user traffic and collecting passwords.

Packet sniffers come in several forms. Some packet sniffers used by network technicians are single-purpose hardware solutions. In contrast, other packet sniffers are software applications that run on standard consumer-grade computers, using the network hardware provided on the host device to perform packet capture and injection tasks.

What Are Packet Sniffers and How Do They Work? (1)

How Packet Sniffers Work

Packet sniffers work by intercepting and logging network traffic via the wired or wireless network interface on its host computer.

On a wired network, the information that can be captured depends on the structure of the network. A packet sniffer might be able to see traffic on an entire network or only a certain segment; it depends on how the network switches are configured. On wireless networks, packet sniffers usually capture one channel at a time, unless the host computer has multiple wireless interfaces that allow for multichannel capture.

Although most packet sniffers in use these days are software, hardware packet sniffers still play a role in network troubleshooting. Hardware packet sniffers plug directly into a network and store or forward the information they collect.

Once the raw packet data is captured, the packet sniffing software analyzes it and presents it in a readable form so that the person using the software can make sense of it. The person analyzing the data can view details of the interaction between two or more nodes on the network.

Network technicians use this information to determine where a fault lies, such as determining which device failed to respond to a network request.

Hackers use sniffers to eavesdrop on unencrypted data in the packets to see what information is being exchanged between two parties. They can also capture information such as passwords and authentication tokens if they are sent in the clear. Hackers are also known to capture packets for later playback in replay, man-in-the-middle, and packet injection attacks that some systems are vulnerable to.

Software Tools Commonly Used in Packet Sniffing

Like most people, network engineers and hackers love free stuff, which is why open source and freeware sniffer applications are often their tools of choice. One popular open-source offering is ​Wireshark, previously known as Ethereal. Use it to sniff your packets in the field, save them to a CAP file, and analyze them later.

Protect a Network and Its Data From Hackers Using Sniffers

If you're a network technician or administrator and you want to see if anyone on your network is using a sniffer tool, check out a tool called Antisniff. It detects if a network interface on your network has been put into promiscuous mode. Don't laugh; that's the actual name for it, and it's the required mode for packet capture tasks.

Another way to protect your network traffic from being sniffed is with encryption, such as Secure Sockets Layer (SSL) or Transport Layer Security (TLS). Encryption won't prevent packet sniffers from seeing source and destination information, but it can encrypt the data packet's payload so that all the sniffer sees is gibberish.

Any attempt to modify or inject data into the packets fails because messing with the encrypted data causes errors that are evident when the encrypted information is decrypted at the other end.

Sniffers are great tools for diagnosing down-in-the-weeds network problems. Still, they are also useful for hacking purposes. It's essential for security professionals to familiarize themselves with these tools so they can see how a hacker might use them on their network.

Types of Information Packet Sniffers Gather

Although packet sniffers are tools of the trade for network engineers, they are also prevalent in some reputable antivirus software and as malware in nefarious email attachments.

Packet sniffers can gather almost any type of data. They can record passwords and login information, along with the websites visited by a computer user and what the user viewed while on the site. They can be used by companies to keep track of employee network use and scan incoming traffic for malicious code. In some cases, a packet sniffer can record all traffic on a network.

Packet sniffers are valuable because they limit malware and are valuable for troubleshooting network problems, but they should be used with robust security software to prevent their misuse.

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What Are Packet Sniffers and How Do They Work? (2024)

FAQs

What Are Packet Sniffers and How Do They Work? ›

A packet sniffer — also known as a packet analyzer, protocol analyzer or network analyzer — is a piece of hardware or software used to monitor network traffic. Sniffers work by examining streams of data packets that flow between computers on a network as well as between networked computers and the larger Internet.

What do packet sniffers involve ____________? ›

Explanation: The function of packet sniffers is to just silently receive the packets flowing in the channel. If they inject any packets into the channel, they might alert the other users about the intrusion.

What is a packet sniffer quizlet? ›

sniffer. Also known as a packet sniffer. An application that monitors,filters, and captures data packets transferred over a network.

How does sniffing work? ›

Sniffing is a process of monitoring and capturing all data packets passing through given network. Sniffers are used by network/system administrator to monitor and troubleshoot network traffic. Attackers use sniffers to capture data packets containing sensitive information such as password, account information etc.

How does packet capture work? ›

Packet Capture is a networking term for intercepting a data packet that is crossing a specific point in a data network. Once a packet is captured in real-time, it is stored for a period of time so that it can be analyzed, and then either be downloaded, archived or discarded.

What is a packet sniffer and how does it work? ›

A packet sniffer — also known as a packet analyzer, protocol analyzer or network analyzer — is a piece of hardware or software used to monitor network traffic. Sniffers work by examining streams of data packets that flow between computers on a network as well as between networked computers and the larger Internet.

How do sniffers work? ›

Sniffers work by capturing internet traffic and analyzing the data streams to uncover the nature — or even the specific contents — of data sent across a network. Just as cars make up road traffic, internet traffic consists of packets of data traveling through a network.

Which of the following is the purpose of a packet sniffer? ›

A sniffer is a program that monitors and analyzes network traffic, detecting bottlenecks and problems. Using this information, a network manager can keep traffic flowing efficiently.

What is true about packet sniffer? ›

What is true about packet sniffers? Legitimate sniffers are used for routine examination and problem detection. Unauthorized sniffers are used to steal information. Packet sniffers are relatively easy to detect.

How does a packet sniffer like Wireshark work? ›

Wireshark is the most often-used packet sniffer in the world. Like any other packet sniffer, Wireshark does three things: Packet Capture: Wireshark listens to a network connection in real time and then grabs entire streams of traffic – quite possibly tens of thousands of packets at a time.

Is packet sniffing a bad thing? ›

Packet sniffing attacks can potentially represent a significant threat to network security, involving methods where attackers monitor network traffic to illegally access and manipulate sensitive data. Understanding these attacks is crucial for implementing effective security measures and preventing potential breaches.

Can packet sniffing be detected? ›

To detect a sniffer on a network, identify the system on the network running in promiscuous mode. The ping method is useful in detecting a system that runs in promiscuous mode, which in turns helps to detect sniffers installed on the network.

What is the function of sniffing? ›

Sniffing, accompanied by a series of rapid upward jerks or vibrations of the nose, is associated with reception of volatile or airborne odors and is often a prelude to direct, nuzzling contact with a scent mark.

Are packet sniffers legal? ›

Packet sniffing is legal for the purposes of network management and when used only on the part of the network for which the person or organization conducting the sniffing is responsible.

What are packets and how do they work? ›

In networking, a packet is a small segment of a larger message. Data sent over computer networks*, such as the Internet, is divided into packets. These packets are then recombined by the computer or device that receives them.

What are the two types of packet sniffers available? ›

There are two main types of packet sniffers:
  • Hardware Packet Sniffers. A hardware packet sniffer is designed to be plugged into a network and to examine it. ...
  • Software Packet Sniffers. Most packet sniffers these days are of the software variety.

What does packet sniffing involve? ›

A packet sniffing attack works by monitoring network traffic and collecting data traveling through your network, to and from the internet. The “sniffed” data might include personal information like banking details or login credentials, or it could simply include any data that passes through the network.

What are the two components of a packet sniffer? ›

A packet sniffer, sometimes called a packet analyzer, is composed of two main parts. First, a network adapter that connects the sniffer to the existing network. Second, software that provides a way to log, see, or analyze the data collected by the device.

What do sniffers eat in Minecraft? ›

What do Sniffers eat. The only thing Sniffers eat are Torchflower Seeds. The only way to get these is by finding and hatching a Sniffer Egg first. But once you feed a torchflower seed to them, it'll heal them for two hearts, send them into Love Mode, and make them breed.

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