Eavesdropping attacks occur through the interception of network traffic. By eavesdropping, an attacker can obtain passwords, credit card numbers, and other confidential information that a user might be sending over the network. Eavesdropping can be passive or active
Passive eavesdropping — A hacker detects the information by listening to the message transmission in the network.
Active eavesdropping — A hacker actively grabs the information by disguising himself as a friendly unit and by sending queries to transmitters. This is called probing, scanning, or tampering.
Detecting passive eavesdropping attacks is often more important than spotting active ones since active attacks require the attacker to gain knowledge of the friendly units by conducting passive eavesdropping before.
Data encryption is the best countermeasure for eavesdropping.
An eavesdropping attack starts with a piece of malware that allows attackers to plant the eavesdropping software or the packet sniffer on victims’ computers. The malware could enter devices when users click a malicious link in a phishing email. It could also be obtained by downloading infected software or applications. The sniffer could also be planted on an unsecured network.
The attackers can then monitor the software or preprogram it to send the data automatically. A hypothetical scenario that is not too far-fetched is this: A payroll officer was at the airport when he remembered he needed to send the company’s payroll report to his manager. He connected to the airport’s open Wi-Fi network and emailed the report. Unbeknownst to the payroll officer, an attacker was able to intercept the email and download the report that contains attendance logs and employees’ banking information.
An eavesdropping attack can also make way for man-in-the-middle (MitM) attacks where threat actors can modify messages and impersonate one of the communicating parties. In our hypothetical scenario, the attackers could alter the message and enter their bank details, so the payroll payments go to them.
Eavesdropping Attack Effects
The theft of sensitive details can result in account takeovers, identity theft, and financial damage. Attackers also stand to gain more by selling the stolen personal information on the Dark Web. Here are a few effects of eavesdropping attacks:
Privacy loss: Every company has confidential information that can damage its reputation if the data is made public. Eavesdropping attacks allow criminals to obtain vital business information, ideas, and conversations exchanged within a target organization, thus encroaching on its privacy.
Identity theft: Attackers can listen to any employees’ private conversations to get login credentials and use them to access restricted storage devices. The individuals don’t only lose their identity but cause their organization harm as well.
Financial loss: Cybercriminals who have confidential data can access vital business applications anytime. They can threaten to expose the information unless the victim pays a high price or sell it to competitors. They earn while the information’s owners lose money.
Avoiding an Eavesdropping Attack: Best Practices
Avoiding eavesdropping attacks calls for several tried-and-tested cybersecurity measures, including the following:
Do not connect to unsecured networks, especially when conducting sensitive transactions, as attackers can easily exploit them. As much as possible, avoid connecting to open Wi-Fi networks available in airports, coffee shops, and hotels.
Use different passwords for every account and change them regularly. That way, even when attackers get hold of one of your passwords, they won’t be able to take over your other accounts.
Use military-grade encryption (256-bit), so even if an eavesdropping attack occurs, attackers won’t be able to see the encrypted data. Using virtual private networks (VPNs) is one way to encrypt your network traffic.
For organizations, network segmentation or dividing the network so each department has different access rights may help. The sales team, for example, does not need access to the payroll system.