Unmasking sniffing attacks: How to protect your network

What is a sniffing attack?

In the realm of cyber security, a sniffing attack intercepts and monitors traffic on the internet. By intercepting and analysing data packets travelling between devices on a network, attackers can gain unauthorised access to sensitive information. This can include passwords, financial data, personal communications, and more.

How does a sniffing attack work?

This hacking technique captures all data packets travelling through a network using specialised software or hardware tools known as network sniffers or packet analysers. These tools are designed to capture and decode data packets that span a network. By doing so, attackers can extract valuable information about the network's architecture and transmitted data.

Types of sniffing attacks explained

There are two main types of sniffing attacks: passive and active.

Passive sniffing attacks

Passive sniffing attacks are subtle and stealthy. In this type of attack, the attacker silently monitors network traffic without altering or disrupting it. This method allows the hacker to remain undetected while extracting valuable information.

For example, a hacker might deploy a wireless sniffer to intercept data packets transmitted over an unsecured Wi-Fi network. This could include sensitive information like login credentials, emails, or financial transactions via online banking.

Active sniffing attacks

Active sniffing attacks are more aggressive. In these scenarios, hackers inject themselves into the network communication process, potentially altering or rerouting data packets.

One prime example is ARP poisoning, which involves manipulating a targeted device or router's Address Resolution Protocol (ARP) cache. By sending false ARP messages, attackers can redirect traffic through their own system, allowing them to intercept and analyse the data.

Common sniffing attack methods

LAN sniffing: A LAN sniffer targets the internal Local Area Network (LAN) and scans for live hosts, open ports, and server inventory. In this context, attackers exploit port-specific vulnerabilities within the LAN.

Protocol sniffing: This type of attack is based on the specific network protocols in use. Hackers focus on protocols like ICMP, UDP, Telnet, PPP, DNS, and others to intercept and analyse relevant data packets.

ARP sniffing: ARP poisoning or packet spoofing attacks rely on captured data to construct a map of IP addresses and their associated MAC addresses. This information is then used to manipulate network traffic.

TCP session stealing: Hackers employ TCP session stealing to monitor and acquire detailed traffic information between source and destination IP addresses. This includes port numbers, service types, TCP sequence numbers, and transmitted data.

Application-level sniffing: This technique involves targeting applications running on a server to plan application-specific attacks. By analysing the application's behaviour, attackers can identify vulnerabilities and potential exploits.

Web password sniffing: HTTP sessions created by users are intercepted, allowing sniffers to capture user IDs, passwords, and other sensitive information.

Tips to prevent sniffing attacks

Here are some steps to minimise the risks of sniffing attacks on your network.

Encrypt your data: Use encryption protocols like SSL/TLS to protect data in transit. Sniffing operates at the packet level, so if packets are encrypted, sniffers can detect anything. Never send sensitive information over an unencrypted connection.

Always use a VPN: Use a Virtual Private Network when connecting to an external or public Wi-Fi network. A VPN adds an extra layer of security and protects data packets sent and received on your network.

Implement firewalls: Robust firewalls can filter out suspicious traffic and prevent unauthorised access, including brute force attacks.

Regularly update your software: Ensure all network devices and applications are up to date with the latest security patches.

Use anti-virus software: Ensure that all computers on your network are adequately protected with anti-virus and firewall software. Installing a strong anti-virus tool can help protect your devices from any sniffers hiding out on your computer or network. It can also help block malware, viruses, and other threats.

Use Intrusion Detection Systems (IDS): IDS tools can detect and alert you to suspicious network activities, helping to mitigate potential threats.

Segment your network: Employ network segmentation based on user permissions, authentication, and user verification. Dividing our network into smaller, more manageable segments limits the impact of a potential attack.

Use robust authentication and access controls: Enforce strong password protection and implement strict access controls like multi-factor authentication (MFA).

Conduct employee training: Educate your employees about the best practices for network security and how to identify suspicious activities.

A final word about sniffing attacks

Hackers can intrude on any network using a packet sniffer and capture data packets transmitted. Understanding the intricacies of these attacks allows organisations and individual users to implement more robust security measures to fortify their networks and avoid potentially devasting breaches. For more information on how to prevent sniffing attacks, contact us at enquiries@xiphcyber.com.