What is IP Spoofing? | CHEQ


From small-scale email schemes to large company-wide breaches, fraudulent activities are becoming more and more of a threat.

Today, suspicious activity is even more challenging to detect, with attackers using IP spoofing to guarantee their anonymity while simultaneously appearing as a trusted IP address.

Here are a few things you should know about IP spoofing, as well as how to identify and prevent it.

Frequently Asked Questions

Q: What is IP spoofing?

A: Internet protocol (IP) spoofing involves sending packets with forged source IP addresses.

Q: What is the purpose of IP spoofing?

A: You can use IP spoofing to conceal the source of an attack, bypass security measures, and conduct man-in-the-middle attacks.

Q: How does IP spoofing work?

By altering the source address of an IP packet, IP spoofing bypasses security measures that block or permit traffic from certain IP addresses. A packet is then forwarded by an intermediate router, which determines the path to the destination device based on the destination address.

Q: What are the two main types of IP spoofing?

A: Typically, 2 types of IP spoofing exist: source IP spoofing and MAC (Media Access Control) address spoofing. MAC address spoofing alters the address of a device, while source IP spoofing alters the address of an IP source packet.

Q: Can IP spoofing be used for legitimate purposes?

A: While IP spoofing is often used for malicious purposes, it can also be used for legitimate ones, such as load balancing and network testing.

Q: How can I protect myself from IP spoofing attacks?

A: There are several safety measures you can take to protect yourself from IP spoofing, these include; implementing multi-factor authentication, using a firewall to block suspicious traffic, and keeping your software and devices up-to-date with the latest security patches. You should also use strong, unique passwords for all of your accounts and be cautious when opening emails or clicking on links from unknown sources.

What is IP Spoofing?

IP spoofing is when a device sends Internet Protocol (IP) packets with a forged source IP address. In an IP Spoofing attack, a ‘spoofed’ source address can impersonate another computer system, making it difficult to know where the attack came from. This type of cyberattack is used for mining sensitive data, hijacking computers for malicious purposes, or perpetrating distributed denial of service (DDoS) attacks.

Click hijacking attacks increased 125% in 2022. Learn more in our State of Fake Traffic 2023 report.

An attacker may be motivated to use IP spoofing for a number of reasons, including:

  • Hiding the true source of an attack: By spoofing the source IP address of the traffic, an attacker can make it difficult to trace an attack back to its true origin. This prevents any authority from tracing the attack back to the perpetrator.
  • Bypassing security measures: Some security systems may block traffic from certain IP addresses or allow traffic from certain IP addresses. An attacker can use IP spoofing to bypass these security measures and alerts by appearing to be a trusted IP address.
  • Conducting man-in-the-middle attacks: IP spoofing can be used to conduct man-in-the-middle attacks, where an attacker intercepts traffic between two devices and can view, modify, or block the traffic as desired.

However, it’s important to note that while IP spoofing can be used to conduct malicious activities, it also is used for legitimate purposes, such as load balancing and network testing.

How Does IP Spoofing Work?

Every bit of information that the internet processes is encoded into an IP ‘packet’ using a source address and an IP ‘packet’ using a destination address. The destination packet tells the internet where to direct it, while the source packet tells the destination where it came from. This process allows the destination packet to route a user to the correct machine.

When a destination packet is sent, it transits through an intermediate router, also known as a transit router or relay router. This router is what connects the source to the destination. However, Intermediate routers do not generally verify the source addresses of the traffic they forward. Instead, they use the destination address of the packet to determine the path to the destination device. IP spoofing exploits this by using a fake source address, similar to sending a letter in the mail with a fake return address.

Because the attacker is only changing the source address, a victim sees the overall packet as a trusted source and accepts it. Networked systems dependent on IP address authentication can be bypassed simply by one breach. This is one of the reasons why a multi-step verification system is becoming more and more common in today’s online environment.

Types of IP Spoofing

The type of attack depends on the attacker’s motives and target. Below are two of the most common types of IP spoofing, with the main difference between them being the type of identifier that is being altered; source vs. device.

Source IP Spoofing

In Source IP spoofing, an attacker modifies the address of an IP source packet, making it appear to have been sent from a different IP address than the true source. By using this technique, attackers are able to bypass security measures that block or permit traffic from certain IP addresses.

MAC (Media Access Control) Address Spoofing

Every network device has a MAC (Media Access Control) address, which allows it to be identified on a network. In MAC address spoofing, attackers modify the address of a device, so that it appears to be a different MAC address than the true MAC address.

How Hackers Use IP Spoofing in Cyberattacks

The complexity of IP spoofing allows for it to show up in multiple ways, subsequently posing multiple threats. IP spoofing can be used to launch a variety of attacks on computer networks, including:

Distributed denial of service (DDoS) attacks

In a DDoS attack, an attacker uses IP spoofing to send a large volume of traffic, usually via source IP spoofing, to a target network in an attempt to overwhelm and prevent it from accessing the web. This can make it more difficult to trace the attack back to its true origin, as the traffic appears to be coming from a different IP address than the true source. DDoS attacks use a large volume of traffic and result in an equally large outcome; a network-wide internet disruption, for example.

Man-in-the-middle (MitM) attacks

In a man-in-the-middle attack, an attacker intercepts two devices – one sending and one receiving – and views, modifies, or blocks the traffic without the receiver knowing. This allows for information theft, directing users to fake sites, and more. Confidential information from MitM attacks collect over time, and hackers can then use or sell this information. Both source IP spoofing and MAC address spoofing can be used to conduct a MitM attack.

Masking Botnet Devices

When masking botnet devices, an attacker uses IP spoofing to hide the identity of a network of compromised devices (i.e. a botnet). In these instances, hackers control a network of compromised devices from a single computer, which in turn performs malicious activities on their behalf. This makes it more difficult to identify the source of the attack and attribute it to a specific botnet. Masking botnet devices is often a tactic used in conjunction with DDoS attacks, as it can create large volumes of traffic from a single source. An attacker can use either IP spoofing or MAC spoofing (or both) as part of their efforts to mask the presence and activity of a botnet.

Application-layer attacks

In an application-layer attack, the source IP address in the header of a packet is altered and sent to a destination. These attacks target the application layer of the Open Systems Interconnection (OSI) model, which is responsible for interacting with applications and providing services to them (HTTP, HTTPS, FTP, and SMTP, for example). Altering the IP address in the header allows attackers to bypass security measures that are based on IP address filtering. Application layer attacks can be used as part of a MitM attack to exploit vulnerabilities in application-level protocols or services. They also are commonly used in email spoofing attacks, where the “from” field is altered to appear as a trusted sender.

How to Detect IP Spoofing

IP spoofing can be difficult to detect, which makes it a strong threat to an organization’s network. However, below are a few common tools that organizations can use to monitor and analyze traffic, alerting them to threats when they arise.

Packet Filtering

Packet filtering is a technique that involves inspecting headers of incoming or outgoing packets, and allowing or blocking each packet based on a set of rules or criteria. Configurations can be made against IP spoofing by blocking any source IP addresses that do not match the predetermined source of origin.

Ingress Filtering vs. Egress Filtering

When packet filtering, each packet is inspected based on its direction of traffic:

  • Ingress filtering: the inspection of all incoming packets
  • Egress filtering: the inspection of all outgoing packets

Network monitoring

With network monitoring, traffic is continuously tracked to detect and identify potential security threats or unusual activity. IP spoofing attacks can be prevented with network monitoring by detecting and alerting suspicious traffic that may be indicative of an IP spoofing attack. A sudden increase in traffic from a particular network or device could indicate an IP spoofing attack.

Two common detections that network monitoring can alert to are:

  • Unauthorized access to network resources
  • Unexpected network disruptions or outages

How to Defend Against IP Spoofing

While IP spoofing can be hard to detect, there are several steps that you can take to prevent it from attacking you or your organization’s network. Below are a few recommended security measures to protect you and your organization from IP spoofing:

  • Firewalls: Incoming packets with spoofed IP addresses can be blocked by a firewall, if properly configured.
  • Using IP-level Encryption Protocols: When IP addresses are encrypted, it makes it harder for an attacker to spoof them, as they would have to decrypt them first.
  • Use of secure protocols: By authenticating the sender’s identity, protocols such as Secure Sockets Layer (SSL) and Transport Layer Security (TLS) can help prevent IP spoofing.
  • Updating and patching your systems: Keeping your software and hardware up todate can help prevent IP attacks by protecting against possible vulnerabilities.
  • Network segmentation: Dividing the network into smaller segments can make an IP spoofing more unlikely for an attack, as they would need to compromise multiple segments in order to access sensitive resources.
  • Use of source IP address filtering: Configuring devices to only accept traffic from trusted sources, based on the source IP address can help to prevent spoofed IP addresses from breaching a network.
  • Leveraging bot mitigation software: Bot mitigation software can monitor network traffic for suspicious activity, such as IP spoofing, and alert network administrators or take action to block the traffic.

Consider Comprehensive Go-to-Market Security

If the above seems like a heavy lift–that’s because it is. Manually mitigation is possible, to a certain extent, but it’s extremely time-consuming, even when leveraging external proxy blocklists and tracking scripts to identify bad traffic.

For businesses serious about security, a comprehensive go-to-market security platform will help automatically detect and block invalid traffic and provide additional insight into marketing analytics.

Our platform, CHEQ, leverages thousands of security challenges to evaluate site traffic in real-time, determine whether a visitor is legitimate, suspicious, or invalid, and take appropriate action to block or redirect that user. Book  a demo to see how CHEQ can help you lower your CPA and protect your go-to-market efforts

Latest Posts

Ready to secure your
Go-to-Market efforts?

Get started