How to Prevent Packet Sniffing Attack | Reasons and Prevention Process

As days go by, the world of information and technology is expanding. The security system and application of tech devices also getting smarter day by day. With this, the hackers also getting smarter, they are discovering new tricky techniques to hack a system, device, or server. Packet sniffing is one of the latest tricky techniques that could be a constant threat to any device, server, and system. Though packet sniffing can be used for both good and bad purposes, cybercriminals only use it for malicious purposes.  

Packet Sniffing Attack

What is Packet Sniffing?

Packet sniffing is a process by which online traffic is inspected by using a sniffer (a packet analyzer). The sniffers can come in both software and hardware form. Packet sniffing is a way to monitor the data packets. Through packet sniffing, the network system is monitored and is used to find the slightest faults of a system. For a healthy and secured network connection, packet sniffing is essential.

How Does Packet Sniffing Work?

All our data got divided into smaller packets while traveling through the network systems. These packets contain a lot of data about the sender which includes IP addresses, request type, process, and other contents that get delivered to the intended destinations. This allows the receiver party to identify and assemble them in order.

Criminals and intruders can hold and inspect the data packages during their journey to intended destinations. By using the sniffing software, the criminals and intruders convert the data packages into a readable format. This way is nearly similar to wiretapping, where a listening microchip is planted on your telephone or contacting device by the stalkers or agents to listen to the conversations unanimously. The chip planting process is performed in packet sniffing by installing software and inspecting the data before converting the data packages into a readable format. After the conversion process, it is easy to analyze the data piece by piece.

Categorization of the Packet Sniffing

Based on filtering, packet sniffing attacks are divided into two types, filtered and unfiltered packet sniffing. Picking or capturing certain data packets for inspection is called filtered sniffing. The filtered packet sniffing is applied when the analyzers are looking for specific data, only the contained parts of the data packet are inspected. In terms of unfiltered packet sniffing, all the data packets are analyzed. The data containment doesn’t even matter on unfiltered packet sniffing.

Filtered packet sniffing is applied largely by the security and data experts, social sites, and commercial users, when the unfiltered packet sniffing is not applied largely. Sometimes, servers and websites sell collective data to a third party without the permission of the owner.

What is Packet Sniffing Used for?

As said before, packet sniffing could be used for both good and bad purposes. The cybercriminals and the hackers use it for bad purposes, while the security experts, network technicians, or admins use packet sniffing for good purposes.

The cybercriminals and hackers mainly practice packet sniffing to complete some malicious processes, which includes;

–        Snatching or stealing sensitive and personal information and data, like login credentials, browsing history, debit/credit card information.

–        To spy on a business or person for snatching confidential information that is not allowed to share with third parties.

–        By using packet sniffing, a cybercriminal or hacker could inject malicious codes or viruses into a server, system, or device.

–        Through packet sniffing, cybercriminals and hackers could have illegal access to a network, system, server, or device to make damage.

–        By using packet sniffing, the cybercriminals could conduct TCP hijacking, which could be used for intercepting the packets between the IP address and source.

Besides the above described illegal and unethical use, Packet Sniffing is used for good purposes too. Network technicians, admins, and cybersecurity experts use packet sniffing to accomplish positive tasks, which includes;

–        The network administrator use packet sniffing heavily to check the health and security of a network system. By monitoring the network response, security experts and the network administrator tests the encryption status of the HTTPS connection.

–        Through packet sniffing, cyber experts examine the traffics of plain text passwords, usernames, and other readable data to apply encryption on them.

–        Packet sniffing is a great tool for troubleshooting or diagnosing network issues and application usage, which is necessary to keep the network system healthy and secure.

–        To detect network issues and resolve the packet, sniffing is one of the most essential tools for security experts.

–        Packet sniffing is used to resolve the misconfigurations of a network system, as well as to ensure the most perfect network route for DNS requests.

–        The advertisers apply this method to reach the targeted users. Packet sniffing is used by the advertiser to monitor the interests of targeted users.

–        Packet sniffing could be used for surveilling the employees of a company and stalking rival companies.

So, Packet Sniffing is necessary for network security purposes like troubleshooting, ensuring the most efficient network route to process the DNS request. Though packet sniffing is used for both good and bad purposes, the bad side of it is avoidable.

What are the Sniffing Tools?

The sniffing tools are the software/ application/ program/ hardware that is used to perform packet sniffing. Without a packet sniffing tool, it is nearly impossible to monitor the data packets of a network system or server. A sniffing tool has all the features to monitor the data packets effectively. Here are some sniffing tools that are largely used;

1. Wireshark

The most widely used packet sniffing tool is used by packet sniffers around the world. It offers numerous features that are designed for assisting and monitoring the packet sniffing process. The Wireshark is mostly got popular for its features.

2. Tcpdump

The Tcpdump is a command-line-based packet analyzer that provides the ability to intercept and observe TCP/IP addresses and other packets during the packet transmission over the network system or server. It is largely used by the network and security experts to identify the fault of a network system to fix them.  

3. NetWitness NextGen

Along with the other features, NetWitness NextGen includes a hardware-based sniffing tool that is designed to inspect and monitor all the traffic of a network system. This is largely used by law enforcement agencies around the world.

4. dSniff

It is a combination of sniffing tools that are designed to perform packet sniffing through the different protocols. Sometimes, it is used for snatching personal information.

Packet sniffing becomes easy and efficient with these packet sniffing tools. These tools help the security experts to monitor the traffic and analyze the data flow over a network or server system.

What are Packet Sniffing Attacks?

As said before, the data passes through a network system as data packets. With the help of specialized tools, cybercriminals and illegal intruders monitor and intercept the data packets to facilitate themselves. The data packets carry information of the sender (the user) to the receiver. The sniffing attack means the illegal extractions of unencrypted data through capturing the network traffic. Sniffing attacks are performed for malicious approaches by hackers or cybercriminals.

There is both legal and illegal use of packet sniffing. When packet sniffing is used for illegal purposes (e.g. hacking, data leaking, stealing, injecting malicious codes) it is called packet sniffing attacks. It may cause damage in various ways. The illegal and legal use of packet sniffing is described before.

How to Detect a Sniffer?

Detecting the sniffer depends on the sophistication level of the sniffing attack. The sniffer may go undetected and hide for a long time on a network and server system. There is some software available on the market that can catch the illegal intruder on a network or server system. It is also possible for the sniffers to bypass the security system by creating a false security sense. A sniffer can use anything to intercept your network system, a hardware device/ software installation/ DNS level and other network nodes could be used to sniff. It is pretty hard to detect a sniffer on a practical network, because of its complexity. Since detection is a pretty tough business, some methods could help to render the sniffed information, which would be useless for the attacker.

Every network is divided into some layers, and each layer has a dedicated task to complete. The dedicated task adds the next layer to the previous one. Sniffing attackers may work on various layers, which depends on the attack motive. Despite the importance of the Network layer (3rd layer) and the application layer (7th), the sniffer can intercept or capture the Protocol Data Unit (PDU) from any layer. Among all the protocols, some are pretty much vulnerable to sniffing attacks. Though the secured version of these protocols is also available, some network and server system still uses the unsecured version of these network protocols. So, the risk of information leakage remains considerable. Here are the network protocols that are vulnerable to sniffing attacks;


The HTTP or Hypertext Transfer Protocol is used at the application protocol layer of the Open Systems Interconnection (the OSI) model. It transmits the information in plain text format, which is perfect for a static website that does not require any input from the user. But on the non-static website, this could be a big issue, anyone can set up a MITM proxy and intercept the data flow to cause damage. This is the point where the user interaction needs to be secured, which can be ensured by using the secured version of HTTP. Known as HTTPS, the secured version of HTTP encrypts the data traffic whenever it leaves the application layer protocol (7th layer)

2. POP

Post Office Protocol, also known as the POP, is largely used by email clients to download mails from email servers. Though it can mechanize plain text for communication, it is pretty much vulnerable to sniffing attacks. POP has new secured versions named POP 2 and POP 3 which are more secure than the original version of POP.


Abbreviated as Simple Network Management Protocol, SNMP is used to establish a connection between the network and network devices. To perform the client authentication, it uses several messages for communication between the community strings. It has been modified as SNMPv2 and SNMPv3. The SNMPv3 is the most secure version of it.


TELNET is a client-server protocol that allows and ensures the facility of communication through the virtual terminal. The main problem of TELNET is, it does not encrypt the data flow by default and for this reason, anyone can access the switch or hub that establishes the connection between the server and the client. Nowadays, SSH is used as a replacement for the unsecured TELNET.

5. FTP

File Transfer Protocol or FTP is used to transfer files between the server and the client. To authenticate, it uses a username and password. Any intruder or cybercriminal can easily intercept the data flow and access all the files of the server. It can be replaced by a more secured version that is called SFTP (SSH File Transfer Protocol) or secured by using SSL/TSL.

How to Prevent Sniffing Attack?

Prevention comes after detection. As we said, detection depends on the sophistication level of packet sniffing. However, if you are not able to detect the sniffing attack, don’t worry, you can still beat it by some methods. These below-described methods could help you to beat sniffing attacks;

1. VPN Service

To beat the sniffing attacks, data encryption is necessary. Data encryption offers the most perfect protection against sniffing attacks. To encrypt your data, VPN (Virtual Private Network) service is necessary. The VPN service encrypts your data and passes it through a secured and encrypted network channel system through the internet. This process makes it tough for anyone to decrypt the intercepted data.

2. Avoiding Public Wi-Fi Connection

While using the public Wi-Fi connection to browse the internet, anyone can sniff your information to facilitate themselves with your data. So, it is better to avoid public Wi-Fi connections. In case, you can use a VPN service while using a public Wi-Fi connection.

3. Using a Secured Protocol

Always use a secured network protocol to avoid packet sniffing. Here, it is recommended to use a VPN service as a confirmation of security. Some extensions or add-ons could help you to increase the security of the internet protocol.

4. Upgrade Security Software

An antivirus tool provides you with around-the-clock protection against malware, virus, Trojans, worms, spyware, and other security threats. To knock out the injected virus on the system by the sniffers, you need to use an antivirus tool.

5. Safe Browsing

To avoid packet sniffing attacks, you need to avoid all unencrypted websites. Browsing unencrypted websites increases the risks of packet sniffing attacks. Always remember to avoid spam mails, unusual pop-ups, and never download any content from a non-reputed site.  

6. Network Monitoring and Scanning

To protect the commercial network or server system from packet sniffing attacks, it is always better to hire professional network administrators and IT professionals. They will monitor and scan the network and server system. It will keep your system away from packet sniffing attacks and other cyber threats.

Frequently Asked Questions (FAQs)

What is a Wi-Fi Attack?

Cybercriminals and hackers can create fake Wi-Fi to intercept and facilitate themselves with the user data. Wi-Fi attacks are a kind of malicious attack that is performed against wireless networks by tricking the Wi-Fi security to steal the user information (e.g. DDoS, eavesdropping).

Is Packet Sniffing Ethical or Unethical?

Packet sniffing has both ethical and unethical uses. It depends on the purpose of packet sniffing. When it is performed for ethical use (e.g. network diagnosing, surveilling, advertising) it is ethical, and when it is performed for unethical use (e.g. hacking, data leaking, injecting malicious codes) it is unethical.

Can Sniffing Be Used for Complex Hacking?

Yes, packet sniffing could be used for complex hacking. Moreover, through packet sniffing, you can crack down network and server systems. A packet sniffing attack on your network or server system could be a warning for getting affected by complex hacking.


Now, you already know enough about packet sniffing and its usefulness, protection, and detection process. Some security steps can help you to avoid the packet sniffing attack. Always browse safely to avoid cyber issues. That’s all for today, see you again.

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