IP Spoofing – A Comprehensive Guide For 2021


Your identity on the internet, whether you are an individual or a collective entity, is determined by your IP address. Bear in mind the fact, however, that this identity is not as secure as we’d like it to be and continuously stands the risk of getting stolen and misused. With your identity at their disposal, the perpetrator in question can not only tap into your traffic and reserves of sensitive data but also commit cybercrimes of extraordinary degree under your name. In IT circles, this is commonly referred to as IP spoofing.

To define spoofing in the literal sense of the word refers to the act of presenting false information as the incredible truth. Spoofing attacks are widespread and affect several fields in their wake. In computer networking, they are most commonly identified in the form of IP spoofing attacks. The majority of computer networks out there do not make use of source IP filtering. As a result, malicious users get the opportunity of inserting an arbitrary address into an outgoing packet of data. This, in turn, makes the IP packers in question seem to appear from a trusted machine falsely.

  1. What is IP Spoofing?
  2. How Does IP Spoofing Work?
  3. What Makes IP Spoofing Possible?
  4. Types of IP Spoofing
  5. Dangers of IP Spoofing
  6. How Can You Detect IP Spoofing?
  7. How Can You Prevent IP Spoofing?
  8. Advantages and Disadvantages of IP Spoofing
  9. Common IP Spoofing tools

1) What is IP Spoofing?

IP spoofing takes place when a user or a hacker modifies the original IP address of a packet to a fake one, subsequently making it seem as if the traffic is originating from a legitimate source, to begin with. Alternatively, hackers also occasionally resort to masking the receiver’s IP to stage a spoofing attack. It is a form of cyber attack where the user’s original identity is either stolen or misused to impersonate another user. The objective of an IP spoofing attack is to hack into systems with the aim of mining into sensitive data, turning computers into zombies, and launching Denial of Service (DoS) attacks.

2) How Does IP Spoofing Work?

To gain an in-depth understanding of the inherent nuances of IP spoofing meaning, one must first acquaint themselves with some fundamentals of the internet at the outset. Firstly, it is important to remember that whenever data is transmitted over the internet, it always takes place in the form of packets. These packets are independent of one another. Post transmission, the packets are reassembled at the receiver’s end to be decoded.

Every packet comprises an IP address header that possesses data about the IP address of the sender and the receiver and other relevant information about the packet under consideration.

Usually, an IP spoofing attack occurs when the IP address of the source is altered to impersonate the IP address of another trusted or legitimate source. For instance, this source could be a computer or system that is part of a legitimate and credible network. Since the source appears to be authentic, the data ends up getting accepted. The cyber attacker can then use a variety of IP spoofing tools to change the IP address header. Once the address has been externally tampered with, there is no way for the receiver to identify and gauge it. It is primarily because IP spoofing in network security predominantly takes place at the network level.

3) What Makes IP Spoofing Possible?

The internet traffic gets segmented into various packets before getting transmitted to and received by its multiple users. At the source, their transmission takes place individually and independent of one another. At the destination, which is usually a website’s server or a receiver’s device, they are assembled to derive the data they carry. In a typical connection, the transfer of the data occurs under a predefined protocol. In computer networking circles, this protocol is called the TCP/IP protocol. Though it dictates all the traffic on the internet, the TCP/IP protocol is not without its own loopholes.

For successfully transferring and exchanging information between the sender and the receiver, the protocol has to complete a three-way TCP handshake. The breakdown of this handshake has been listed below:

  • To begin with, the receiver in question gets an SYN message from the source. It serves to establish a connection between the two devices and allow them to synchronize their sequence numbers.
  • Upon receiving the SYN message, the receiver transmits an ACK message, which is more or less acknowledging the SYN message’s reception.
  • Subsequently, the source transmits an SYN-ACK message back to the receiver, thereby successfully confirming a secure connection.

To stage the most basic IP spoofing attack, all one has to do is intercept the TCP handshake before starting the last stage of the protocol mentioned above. Instead of allowing the source to transmit an SYN-ACK message, the hacker delivers a fake confirmation that contains their MAC or device address and a spoofed IP address of the actual sender. As a result, while the receiver is left thinking they are connected with the true sender, in reality, all their communications are taking place with a spoofed IP. It can be learned quickly through an IP spoofing tutorial.

4) Types of IP Spoofing

Broadly, there exist four categories of IP spoofing attacks out there:

  • Blind Spoofing: In blind spoofing, the attacker sends out several packets to their target. Usually, these cyber attackers exist outside the local network’s boundaries and are mostly unaware of how transmission occurs on the said network. Hence, before staging the attack, they tend to first concern themselves with learning the sequence in which the packets are read.
  • Non-Blind Spoofing: In non-blind spoofing, the attacker and their target exist on the same subnet. It gives them the liberty to sniff the wire to determine the sequence of the packets. Once the knowledge of the sequence is at their disposal, the hacker gets to bypass authentication by impersonating another trusted and legitimate machine.
  • Denial-of-Service (DoS) Attack: In these kinds of attacks, the perpetrator in question sends packets and messages from a host of different machines to their target. Hence, determining the IP address spoofing source in the case of DoS attacks becomes an extremely complicated affair. Consequently, as one cannot track the source of the attack, they fail to block them as well.
  • Man-in-the-Middle Attack: In these attacks, the malefactor intercepts the messages or the packets transmitted and exchanged between two other communicating systems.

5) Dangers of IP Spoofing

Over time, hackers and malefactors have increasingly used spoofing attacks to inflict large-scale damage and cause an unyielding nuisance. Listed below are a few of the most widely-occurring hostile uses of IP spoofing:

  • Bypass IP Authorization and Firewalls: Getting past fundamental security measures that depend entirely on blacklisting (such as firewalls) are among the primary reasons why hackers and cyber attackers resort to IP spoofing attacks in the first place. It essentially means that even if the malefactor’s original IP happens to be on the blacklist and blocked, they still get the option of bypassing it simply by making use of a spoofed IP. Additionally, this also extends to systems with whitelists in place intending to allow connections only from trusted and legitimate IPs. It is why most companies out there are discouraged from relying solely on IP authorization and instead nudged to avail the services of other authentication methods at their disposal.
  • DoS Attacks: A DoS attack serves the purpose of bringing down a server or a website by subjecting them to an immense number of fraudulent requests. Usually, these requests are issued by devices infected by botnet worms. In most of these cases, the owners themselves are unaware that they’re serving as a cog of the cyber attacker’s private army. Additionally, one can also make use of IP spoofing to redirect deceitful communications.
  • Man-in-the-Middle Attacks: These attacks are mostly native to airports and cafes where the Wi-Fi locations are usually unsecured. None of the information that you exchange during a man-in-the-middle attack is secure, for it runs the constant risk of getting sniffed by the hacker who’s intercepting all the communication between the two parties involved. Using a VPN (Virtual Private Network) is often considered among the best ways to ensure a network from a man-in-the-middle attack.

6) How Can You Detect IP Spoofing?

If you wish to protect your system from an IP spoofing attack, you first need to be well-versed with the various ways in which you can detect an attack in the first place. A common method of going about this is to scan the system to check for inconsistencies, such as source IP addresses that do not sync with the company’s network’s remaining addresses. The two most commonly used detecting techniques are:

  • Routing Methods: Using routers enables us to determine every IP address’s origin points on the network. Additionally, they also help us find out about the network interface from which the IP address is hailing. As a result, they help avoid all those packets not meant to be received by a particular interface.
  • Non-Routing Methods: At the outset, there exist a host of ways, both passive and active, using which one can determine whether the packet received is spoofed in nature or not. Network monitoring tools, such as Netlog, can be used to scan the packets’ external interfaces in question. They also help detect IP spoofing by facilitating the comparisons of process accounting logs between systems present on the internal network.

7) How Can You Prevent IP Spoofing?

The most commonly adopted practices for preventing and controlling spoofing attacks are:

  • Making use of an authentication system based upon the trading of keys such as IPsec.
  • Blocking private IP addresses by using ACL on downstream interfaces.
  • Subjecting both inbound and outbound traffic to filtering.
  • Migrating the web application to IPv6 subsequently helps prevent spoofing through its implementation of authentication and encryption steps.

8) Advantages and Disadvantages of IP Spoofing

Although IP spoofing is, by and large, an illegal activity, it does entail a couple of odd advantages:

  • Multiple Servers: Often, there arise occasions when one requires changing the IP address of the incoming packets of a network to channel them to a different machine or system altogether. Usually, this happens when the user only has one IP address at their disposal, but they require people to enter machines behind the one that owns the actual IP address.
  • Transparent Proxying: IP spoofing also facilitates transparent proxying whenever you require impersonating. Every packet and stream of data travelling through your Linux server includes the destination on a program that is native to the Linux box in the first place.

Now that we’ve discussed the advantages of IP spoofing, let us move on to its disadvantages:

  • Blind Replies: This essentially means that the spoofed IP address will receive the reply packet transmitted from a system instead of the actual attacker.
  • Serial Attack Platform: IP spoofing allows an attacker to maintain a considerable degree of anonymity. They can do so by hijacking a set series of attack hosts. The attacker usually wages their attack on the last host in the attack chain to target the victim. Consequently, this disables the authorities from tracking the origins of the attacker’s base host.

9) Common IP Spoofing Tools

  • Netcommander: This is the most user-friendly arp tool out there.
  • Sylkie: This tool makes use of the neighbour discovery protocol to spoof IPv6 addresses.
  • Aranea: Aranea is a clean and fast spoofing tool that cyber attackers often use to stage spoofing attacks on a network.
  • Isr Tunnel: Isr Tunnel makes use of source-routed packets to spoof connections.


The real-time risks of IP spoofing are rather grave and tend to have irreversible consequences in most situations. However, it is not a menace that can’t be dealt with effectively. Adequate encryption, authentication, and cybersecurity measures must exist in place to prevent this exploitation of a trust-based relationship between two systems on a network.

So, have you made up your mind to make a career in Cyber Security? Visit our Cyber Security Courses for further help. It is the first program in offensive technologies in India and allows learners to practice in a real-time simulated ecosystem, that will give you an edge in this competitive world.


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