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In Security Last updated: September 4, 2023
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It will not be an understatement if we call this the era of cyberattacks when hackers implement a number of innovative methods. Here, we will discuss packet sniffing attacks and how you can prevent them.

Packet Sniffing Attack


Sniffing refers to intercepting and monitoring traffic on a network. It can be done either by using hardware devices designed particularly for sniffing or through an application that captures all data packets passing through a network.

During a sniffing attack, hackers use a packet sniffer to intercept sensitive data that are being transmitted through a network. The main targets of these attacks are passwords, bank details, financial information, private data, and unencrypted emails.

Why Do Hackers Perform Packet Sniffing

  • Recording your online activities 
  • Reading your emails
  • Viewing your passwords and banking details 
  • Infecting a network with viruses or malware
  • Asking for ransomware keeping important files hostage
  • Stealing money from your account
  • Attacking your organizational network

Notable Examples of Packet Sniffing Attacks


BIOPASS RAT and Cobalt Strike Attacks

In 2021, Chinese online gambling organizations faced a watering hole attack where attackers used BIOPASS RAT or Cobalt Strike. It exploited OBS Studio’s live-streaming and tricked users into installing software that also planted BIOPASS RAT malware via scheduled tasks. The entire thing was done during the actual application download.

Password Sniffing Attack

In 2017, FireEye found out about a phishing campaign by APT28 hackers targeting European and Middle Eastern hotel guests. The attackers used an infected document, WiFi sniffing, and the EternalBlue exploit, which was also used in the WannaCry ransomware attack. Opening the document launched a macro that infiltrated the hotel’s network and stole user data.

Browser History Sniffing Attack

In 2018, a research paper titled “Browser History Revisited” exposed flaws allowing website owners to track users even after clearing history. These vulnerabilities used Chrome and Firefox security features and could spread to other browsers.

Security Breach in Payment Systems 

In 2009, Heartland Payment Systems suffered a security breach that exposed credit card data to sniffers. They were fined $12.6 million for poor customer protection against such attacks.

How Does Packet Sniffing Attack Work?

Usually, packet sniffing attacks are only done to gather information about a company before rolling out more severe attacks. Hence, you can consider the sniffing attack as the initial stage of the major attack.

At this stage, hackers inject malicious code into your system to spoof access to MAC addresses, impersonate someone to access a network hub, fake MAC addresses, or alter the DNS cache of a computer.

These approaches will allow hackers to collect data, and they might wait from days to months. Once the information is collected, the attackers plan and execute a more malicious attack. This might include logging in to your account or asking for ransomware by locking your system data. If the stolen packets at the first stage contain personal information, they might use it for a targeted phishing attack

Types of Sniffing Attacks


#1. Password Packet Sniffing

This type of sniffing aims to capture passwords that are being transferred through unencrypted data packets. In this man-in-the-middle attack, hackers steal your personal data when it moves between your device and its destination.

#2. WiFi Packet sniffing

One of the most common types of packet sniffing is WiFi packet sniffing. This attack is done on an unsecured network where hackers use a WiFi sniffer to monitor the transmitting data.

#3. Browser History Sniffing


Web browsers often store login credentials that can be used conveniently to sign in to your favorite websites. Hackers use packet sniffing to get browsing history and login details.

#4. Session Hijacking

When you visit a server during an online session, you are given a session ID. In the case of TCP session hijacking, hackers hijack your legitimate session ID to perform seemingly “authorized” activities on the network for notorious purposes.

#5. JavaScript Sniffers

In this case, hackers inject malicious scripts into the website to collect your private information (passwords, contact information, email ID, bank details) as entered on websites or online forms.

#6. DNS Poisoning Attack


DNS poisoning attack is how attackers reroute the traffic from a legit website to a fake but convincing website. The websites look almost similar and, therefore, can easily trick visitors into entering login credentials without any hesitation.

#7. ARP Sniffing Attack

With ARP sniffing, hackers send false messages on your network to redirect traffic from your IP address to their own. 

#8. DHCP Sniffing

The full form of DHCP is Dynamic Host Configuration Protocol. It automatically assigns an IP address to a device when it connects to a network. During an attack on DHCP, attackers flood the real DHCP server with numerous requests until the IP address can not be distributed anymore.

Then, they create a rogue DHCP server that takes the place of the original. Thus, packet sniffers can monitor data getting transmitted through the network.

How to Prevent Sniffing Attacks


Do Not Use Unsecured Networks

If you have the habit of connecting your computer to any random WiFi network, you need to get over it. Unsecured networks do not have any firewall and antivirus protection, which makes these vulnerable to cyberattacks like packet sniffing attacks. Attackers use these networks to read any data sent over them and monitor network traffic through “free” public WiFi networks. 

Use VPN for Encrypted Data Transfer

Another way to protect your data from sniffing attacks is to use VPN software. When you use a VPN application, your data is encrypted during communication. If a hacker wants to access it, they will need to decrypt it first — which is a complex task. Moreover, sniffers are unable to see which websites you visit when a VPN is used.

Use Antivirus Software


Endpoint devices like computers, laptops, and smartphones are the easiest way for attackers to get into the organizational network. You can improve the security of an endpoint device by installing antivirus software, which will detect a sniffer even before it attacks the device. 

Regularly Monitor Office Networks

Network or system administrators should regularly scan their organizational networks. They can use robust tools for bandwidth monitoring or network mapping to identify sniffing attacks and improve the network environment.  

Be Vigilant During Online Activities


Every day, attackers find out about new social engineering tactics to make you perform security mistakes or give away personal/sensitive information. Be aware of such tricks to avoid getting attacked through fake emails or suspicious links. 

Use a Sniffer Detector Software

There are various sniffing tools available in the market that you can use on your device to prevent it from sniffing attacks.  

Only Visit Websites with HTTPS protocols


When you enter the URL of a website to access it, it should start with “HTTPS.” It means the website uses a secure login that encrypts user interactions being transmitted to the server. So, not visiting a website that only uses HTTP is advisable to prevent sniffing attacks.

Deploy IDS

An intrusion detection system (IDS) keeps a close eye on network traffic and alerts you of unusual activities and prospective intruders. You can deploy it in your organization to scan the network or systems for malicious activities or policy breaches. It also notifies the sysadmins about any potentially dangerous behavior or security breach.

How to Manage Sniffing Attacks


Despite taking all the preventive measures, you could become a victim of the packet sniffing attack. Yeah, you read it right! Here is what you should do after the packet sniffing attack happens to you:

  • As soon as you come to know of this attack, you should disconnect the affected device from the network. It will stop the attacker from causing you any more harm.
  • If it happens to your office computer, you need to inform the IT department or sysadmin about the attack. 
  • Change all the credentials added to the compromised system and its related accounts.
  • If you suspect that the attack involves personal or critical data, notify affected people or regulatory authorities.
  • Try to find out the vulnerability of your network or system that the hackers may have exploited to gain access.
  • Analyze the network traffic and logs to find out the attacker’s activities.
  • Improve your network and system security to prevent future attacks.
  • Talk to a lawyer to discuss your rights and responsibilities about the incident.

Wrapping Up

To safely perform online activities, you must have clear ideas about different cyberattacks, such as packet sniffing attacks. Now that you have read this post, you know how this attack works and how damaging it could be. 

Following the preventive methods mentioned here, you could protect yourself from this attack. You can also stay updated about the latest updates on this field with cybersecurity podcasts.

  • Bipasha Nath
    I am a technical and creative content writer with 10+ years of experience in the relevant industry. My degrees in English and Sociology, coupled with working experience in software development companies, help me understand how technology… read more
  • Narendra Mohan Mittal

    Narendra Mohan Mittal is a Senior Digital Branding Strategist and Content Editor with over 12 years of versatile experience. He holds an M-Tech (Gold Medalist) and B-Tech (Gold Medalist) in Computer Science & Engineering.

    read more
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