IP Spoofing: What is it and How to Prevent it?

In order to commit crimes, cybercriminals rely on a variety of techniques to avoid detection. One such technique is known as Internet Protocol address spoofing, or just IP spoofing.

In this article, we'll cover:

So, if you want to understand IP spoofing and prevent it, this article will be a good place to start.

What is IP Spoofing?

So what is IP spoofing exactly?

We already mentioned that it's a technique used by cybercriminals to avoid online detection, but how?

What IP spoofing does is that it allows cybercriminals to use the IP address of another computer system to infect your computer or device.

This way, the hacker can:

  1. Shut down or flood websites, servers and networks of their victims
  2. Steal people's data and use them for online fraud or identity theft.

By using a different computer's IP address, the attacker will appear as a legitimate and trusted source to most device owners, thus making their task of stealing sensitive data much easier.

IP spoofing enables the cybercriminal to hide their true identity from:

  1. Firewalls and other security software. Since the source IP addresses will appear as trusted, the cybercriminal will be able to bypass firewalls and not get blacklisted.
  2. Computer system alerts. Because computers and networks won't know that they're compromised, they won't send out alerts.
  3. Police. As the cybercriminal's true identity is hidden and anonymous, through spoofed IP addresses, this makes the police's job of identifying them much harder.

How Does IP Spoofing Work?

But how does IP spoofing work exactly?

To answer that question, you will have to understand a bit how IP addresses work in the first place and how data travels across the Internet.

You are probably familiar with IP addresses. Each device on the Internet has its IP address to identify it to other devices connected to that same network.

When data travels across the Internet, it does so in the form of IP packets. Each IP packet contains a packet header and data.

Each packet header is between 20 and 24 bytes long. A packet header holds information on the source IP addresses and destination, as well as other information necessary for the packet to find the best route to its destination IP address.

On the other hand, the data part contains the actual content of the packet, like a web page, email, or file.

So what the cybercriminal does is intercept such IP packets, change their packet headers with spoofed IP addresses and sends them to their destination. That way, the cybercriminal can impersonate another computer system.

What are the Types of Spoofing IP Addresses?

An IP spoofing attack can come in several forms, but the following three are the most common and dangerous:

DDoS Attacks

One common reason cybercriminals use IP spoofing is to overwhelm the computer network with IP packets by launching DDoS attacks, or Distributed Denial of Service, and crash or slow down the server.

Man-in-the-Middle Attacks

Another way cybercriminals employ IP spoofing is to commit man-in-the-middle attacks by modifying the IP packets between the two computers before they reach the recipient. In this case, neither the original sender nor the recipient will know that the source IP address has been altered.

Masking Botnets

Finally, IP spoofing can be used to mask groups of connected computers called "botnets" and that way gain access to the victim's computer. This way, cybercriminals can flood computers, websites and servers with data, send malware and spam and ultimately, crash them.

How to Prevent IP Address Spoofing?

As you can see, IP spoofing can be very dangerous for the very fact that it is so hard to detect.

That said, there are ways to protect your data, computer and network from IP spoofing.

Here is how:

  1. Don't browse on unsecured, public WiFi networks. If you must use a public WiFi hotspot, be sure to use a VPN (Virtual Private Network) to protect your ingoing and outgoing data.
  2. Make sure to update your home network's default username and password that you received from your Internet Service Provider. This is because most routers have a default username and password that is relatively easy to discover, which makes your home network vulnerable.
  3. Safely browse the web. For instance, be sure to avoid unencrypted "HTTP" traffic whenever possible and instead visit URLs with "HTTPS" and the green padlock.
  4. Ignore emails or other messages telling you to "update" your login credentials or other data. These are phishing emails designed by scammers to trick you to reveal your data. Here is how to protect from an email-based phishing attack.
  5. Use a firewall to filter and verify traffic with spoofed IP addresses, block malicious attackers and authenticate their source IP address.
  6. Use packet filtering systems such as ingress filtering. This will allow you to verify that the IP packets come from trusted and legitimate sources and are not from spoofed IP addresses. Ingress filtering inspects the source IP address packet header to do this, while egress filtering monitors the outbound traffic and its packets for legitimate IP source headers.
  7. Finally, be sure to monitor your network regularly for any suspicious activity.

Can IP Spoofing be Done in a Legitimate Way?

Yes, IP address spoofing does have a legitimate use and not just to conduct spoofing attacks.

For instance, a company could spoof an IP address to test their new website and ensure that it works when it goes live.

By doing this, the company can test the website to see that it doesn't get overwhelmed.


As you can see IP spoofing can potentially be very dangerous and it can lead to man-in-the-middle attacks, DDoS attacks and more.

This is why we thought it important to turn your attention to IP spoofing, how it works, why is it dangerous and how to prevent it to help you understand it and protect against it.

Hopefully, we were successful.

And if you want to protect your data even further, be sure to start using an encrypted email service. Sign up to CTemplar: Armored Email and enjoy your privacy and security.