What an eavesdropping attack is, and how to prevent it

What is an eavesdropping attack? 

How does eavesdropping work? 

Eavesdropping attacks typically occur when a user connects to an unsecured network where traffic isn’t encrypted. If they send sensitive data, such as corporate communications between two parties, the lack of encryption allows an attacker to intercept confidential information because it travels across the open network. Through eavesdropping attacks, hackers can steal data like login credentials and confidential business data that they can use to commit identity theft, fraud, blackmail, or even manipulate victims through social engineering.

Methods of an eavesdropping attack 

Eavesdroppers use several different methods to launch their cyberattacks. Here are some of the most common ones:

• Network sniffing. Common in local networks, this eavesdropping cyberattack method involves using packet sniffers to capture and analyze network traffic. Hackers use packet sniffers to monitor data packets traveling across a network. This step allows attackers to potentially intercept sensitive information like usernames and passwords.
• Man-in-the-middle attacks. In a man-in-the-middle attack, the hacker positions themselves between the victim and the intended recipient of information. This eavesdropping attacker finds vulnerabilities that allow them to watch data travel from the victim’s device and that of their intended recipient, ready to intercept and manipulate the communication.
• Wireless eavesdropping. Since wireless signals are broadcast using radio waves, wireless networks are especially vulnerable to eavesdropping attacks. Using tools like wireless sniffers, eavesdropping attackers can intercept data transmitted over these networks. 

Types of eavesdropping attacks

To avoid becoming a victim, it’s crucial to learn what the different types of these attacks look like.

• Passive eavesdropping attack. In this attack, passive eavesdropping attackers covertly review network activity without altering data.
• Active eavesdropping attack. With active eavesdropping, hackers not only intercept data being transmitted between two parties but also actively modify or manipulate that data.
• Email interception. Email eavesdropping occurs when hackers capture emails as they travel between servers. This attack can expose sensitive information like business communications and personal data. It may give attackers the opportunity to exploit vulnerabilities in email protocols.
• VoIP eavesdropping. Voice over Internet Protocol (VoIP) eavesdropping refers to when a malicious actor intercepts and records a conversation transmitted over the internet. They exploit VoIP system vulnerabilities to access confidential discussions.
• Physical eavesdropping. Physical eavesdropping is what you might think of when you hear the term “espionage.” The hacker uses devices like hidden microphones or tapped phone lines to eavesdrop on conversations. This attack tends to require physical access to the target area and is not common in digital attacks.

Active eavesdropping attack vs. passive eavesdropping attack: What are the differences? 

An active eavesdropping attack involves intercepting and manipulating unsecured network communications. In contrast, a passive eavesdropping attack simply involves listening in on the communication without altering it. Because passive eavesdropping doesn't disrupt the flow of data, it's much harder to detect compared to active attacks, which often cause noticeable disturbances in the network’s behavior.

Let’s take a look at a rundown of the differences between active and passive eavesdropping

Examples of eavesdropping attacks

Eavesdropping attacks can occur in many ways and target various communication channels. Here are some examples of how eavesdropping attacks take place:

• Public Wi-Fi interception. In this eavesdropping attack example, a hacker sets up a Wi-Fi hotspot that appears to unsuspecting customers as the cafe’s free public Wi-Fi. When victims connect to the network, the eavesdropping attacker can intercept unencrypted transmitted data like login credentials and financial information.
• Corporate espionage. An eavesdropping attack often involves a business hiring a hacker to steal intellectual property and other confidential documents from a competitor. The hacker infiltrates the competitor’s VoIP system and exploits vulnerabilities in the VoIP infrastructure to covertly record business calls.
• Smart home device exploitation. The convenience of smart home ecosystems like Amazon Alexa and Google Home has made residents vulnerable to eavesdropping attacks. Attackers exploit vulnerabilities in the victim’s operating system, gaining access to devices like smart speakers and security cameras, which enables them to eavesdrop on conversations and monitor the target at home.  

How to prevent an eavesdropping attack

You may be staring at your Amazon Alexa or work computer screen, wondering who is listening in on your private conversations — or who might do it in the future. You can defend yourself against these types of attacks in various ways:

• Implement multi-factor authentication. Employ robust security measures like strong authentication mechanisms that will help to protect your accounts. Multi-factor authentication (MFA) is a tool you can use to add an extra layer of protection to your cybersecurity. Instead of just a username and password to access your accounts, MFA requires at least one other factor, such as a code sent to your cell phone. That way, even if a hacker has acquired your login credentials in an eavesdropping attack, they still won’t be able to access your account.
• Employ network segmentation. To protect sensitive information, network segmentation divides a network into smaller, isolated segments, limiting an attacker's ability to access sensitive data by restricting their movement within the network.
• Set up comprehensive network monitoring solutions. Intrusion detection and intrusion prevention systems can help identify eavesdropping attempts and improve eavesdropping attack prevention.
• Keep your software up to date. Regularly update your operating system and other software as soon as a new update is available. The updates fix vulnerabilities in the operating system that eavesdropping attackers might exploit to gain unauthorized access.
• Practice good password management. One of the best ways to protect yourself from eavesdropping attacks is to create strong passwords using capital letters, numbers, and symbols. Also, never use the same password twice because if a hacker cracks one account, they’ll also have access to others. 
• Enact physical security measures. To prevent eavesdropping attacks, don’t forget about physical security measures. Invest in surveillance cameras and barriers to block listening devices for your office.
• Avoid public Wi-Fi networks. It’s convenient to use public Wi-Fi networks when you’re out on the go, but unless you have a good virtual private network (which we’ll discuss below), it’s not worth the risk. Each time you connect to public Wi-Fi, it could potentially expose you to an unsecured network where you might become the victim of eavesdropping attackers.
• Use a VPN. A virtual private network (VPN) encrypts your online traffic so that you can enjoy secure communication. Virtual private networks like NordVPN use several strong encryption protocols, including DES, RSA, and AES. This protection is especially important when accessing sensitive information on unsecured public networks. When you use a VPN on public Wi-Fi, you can relax and know that your sensitive communications are safe.