What are Sniffers?

Sniffers are the tools or programs designed to intercept and analyze data packets transmitted between devices or systems on wired or wireless networks. These tools assist to capture data packets, thereafter they are analyzed and converted into a format that users can understand . Hence, this enables the user to inspect the contents of the packets and derive significant information. Sniffers are known by many names such as network probes, packet analyzers, ethernet sniffers and many more. They play an important role in network management and security. Some well-known sniffer programs are Wireshark, NetworkMiner, Snort, TCPDump, etc.  

How do Sniffers Work?

There are mainly two techniques with sniffers work namely, active sniffing and passive sniffing, depending on the structure of the network. 

Active sniffing is most suitable for the network with switches. Switches manage traffic in an efficient way by directing data to the device meant to receive it. This technique involves injection of new traffic into the network, thus making it active. This technique is easier to detect due to the additional traffic generated. An active sniffer has to overcome how the switches direct everything to access all network traffic.

On the other hand, Passive sniffing is most suitable in networks using hubs. Hubs connect multiple devices without directing traffic to specific recipients. Here, all devices receive all traffic and thereafter filter out the irrelevant ones. The low-profile nature makes passive sniffing hard to detect. In this scenario, a passive sniffer collects all transmitted data.  

Types of Sniffers

Sniffers are broadly classified into two categories namely, Commercial and Underground sniffers.

• Commercial Sniffers: These are primarily used to maintain and monitor network health. Businesses like Network General Corporation provide commercial sniffers for fault and performance analysis. 
• Underground Sniffers: Generally, the malicious attackers use these sniffers to capture sensitive information. These are installed on routers which result in breach of security of any network traffic and capture confidential data.

What Does a Sniffer Consist Of?

A sniffer comprises of four components:

• Hardware: It utilizes standard network adapters to capture network traffic.
• Capture Drive: It helps to capture network traffic from Ethernet cable. When the traffic is captured and filtration is done, the significant information is stored in a buffer.
• Buffer: It stores captured data until it is full or uses a round-robin method where the new data replaces the old one. 

Decoder: It converts binary network data into a readable format.

Where the Sniffer Shall be Placed?

Sniffers can be placed in various network locations for optimal data capture. It can be:

• Routers
• Cable wires
• Computers
• Network segments connected to the internet

How Can a Sniffer Software be Used?

Sniffing Software can be applied for the following purposes:

1. Resolve Specific Network issues- Sniffers assist to resolve issues like packet loss, incorrect routing and bandwidth overuse, which can slow down or interrupt network performance.
2. Education of Network Security- Sniffers are excellent tools for teaching about real-world network security threats and defenses.
3. Compliance with Data Protection laws- These are used to monitor and ensure that network data handling adheres to regulations like GDPR or HIPAA, which are subject to strict data privacy and security standards.
4. Exploit Network Weaknesses- Sniffers are used by the hackers to find security gaps in networks, such as unencrypted data transmissions for unethical activities like data breaches or cyberattacks. 
5. Steal Sensitive Information- Sniffers are used to intercept credit card details, bank login credentials, and other financial data.

Unethical Use of Sniffing Software

Network sniffing in cybersecurity are not only used for ethical purposes but also used for unethical intentions. Hackers use packet sniffers to sneak into a network and capture all the data transmitted through it. In this way, the hackers are able to know the sites you visit, read your emails and conversations and may know your passwords or other sensitive information. 

Hackers tend to phish people to download the sniffers. They may perform social engineering techniques or phishing emails to trap them. When you visit these websites or open the emails, the sniffer gets installed on your device without your knowledge.

Hackers often target the open networks like public Wi-Fi networks which lack good security. They use packet sniffers to capture data from anyone using the networks. 

How Can You Secure Your Network from Non-legitimate Sniffers?

You can follow and practice the below discussed precautions to protect networks from non-legitimate sniffers. 

• Ensure Website Security- Always prefer to browse websites that use HTTPS protocols. This protocol encrypts the data entered into a user’s device to deliver it to the website, with which they are interacting with safety.
• Use Secured Connection- Prohibit the use of public Wi-Fi networks for crucial activities. Unsecured networks often tend to be harmful and can be compromised easily. Use Virtual Private Network (VPN) when accessing the internet remotely. A VPN encrypts your connection and makes the intercepted data useless for the hackers.
• Be aware of social engineering- Always stay alert against phishing emails and deceptive websites that phishes users to download malicious sniffers.

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