Introduction

The word “spoofing” has a negative connotation and it means the act of fooling. In other words, when someone presents something false as a credible truth it is called spoofing. Spoofing occurs in many fields but in the world of networking IP address spoofing is the most relevant and common. Since a lot of networks do not use source IP filtering, a nefarious user might insert an arbitrary address to an outgoing packet of data to indicate that the IP packers originated from a trusted machine.

In the following sections of this article, we will describe in detail what is IP spoofing, go through some IP spoofing tools, and understand how to prevent IP spoofing.

  1. What is IP Spoofing
  2. How IP Spoofing Works
  3. Types of IP Spoofing
  4. How to detect IP Spoofing
  5. How To Prevent IP Spoofing
  6. Advantages and Disadvantages of IP Spoofing
  7.  IP Spoofing Tools 
  8. Examples of IP Spoofing Attack

1. What is IP Spoofing

The IP spoofing definition is a specific type of cyber attack where someone creates IP (Internet Protocols) packets to masquerade as a legitimate entity. This IP spoofing is done by having a modified address in the IP packets to hide the identity of the user (or impersonate another user) to gain access to other computers. The main aim of IP spoofing is to mine the systems for sensitive data, take them over for malicious use (turn the computers into zombies), or launch DoS (Denial of service) attacks.

2. How IP Spoofing Works

To understand the  IP spoofing meaning in detail and dig into how IP spoofing works let us understand some basics of the internet.

  • Data is transmitted over the internet in form of packets of data (independent of each other) and then reassembled at the receiver’s end.
  • Each packet has an IP address header that contains data about the sender’s IP address, the destination IP address, and information about the packet.

IP spoofing attack happens when the IP address of the source is changed to resemble the IP address of a trusted source (for example another computer on a legitimate network) so that the data gets accepted. The IP address header can be changed by the cyber attacker by using IP spoofing tools. There is no way for the receiver to gauge external tampering since IP spoofing in network security happens at the network level.

3. Types of IP Spoofing

There are mainly 4 types of IP spoofing attack in the internet world:

  • Blind Spoofing – In this type of spoofing, the attacker (who is outside the perimeter of the local network) sends multiple packets to the intended target. The attacker is not aware of how the transmission takes place on this network and needs to know the sequence in which the packets are read (packet 1 first, then packet 2, etc.). 
  • Non-Blind Spoofing – The attacker resides on the same subnet as the target hence s/he knows the sequence by sniffing the wire. After knowing the sequence an attacker can impersonate as another machine to bypass authentication.
  • DoS attack – In a Denial-Of-Service attack, the malefactor sends messages from several different machines making it extremely difficult to find out the source of the IP address spoofing attack. Since one cannot find the source of the attack, there is no way to block the attacks.
  • Man-in-the-middle attack – This attack is done by the attacker by intercepting the packets being sent between two communicating systems.

4. How to Detect IP Spoofing

To prevent your systems from IP spoofing attacks let us first see how is IP address spoofing detected. Some of the ways of detecting IP spoofing are:

  • Check system for any atypical action like active packets on the network which have a source IP address that does not coordinate with the addresses on the organization’s network. For this, a couple of techniques are employed as described below:
  • Routing methods – Routers have a way to know which IP addresses originate with which network interface hence they can know which packets should not have been received by a specific interface.
  • Non-routing methods – There are many active and passive ways for computers to determine if a packet they received is spoofed or not. Network monitoring tools like Netlog can look at the external interface for packets that have addresses of internal domain or a method like comparing process accounting logs between systems on the internal network can help detect IP spoofing.

5. How To Prevent IP Spoofing

There are ways to control and prevent IP spoofing and the most common ones are:

  • Use an authentication system based on the exchange of keys like IPsec.
  • Use ACL on downstream interfaces to deny private IP addresses.
  • Employ filtering (Ingres and Egress filtering) on inbound and outbound traffic.
  • Migrate your web application to IPv6 which cuts down spoofing by implementing encryption and authentication steps.

6. Advantages and Disadvantages of IP Spoofing

Even though IP spoofing is an illegal activity, there are a couple of advantages of IP spoofing:

  • Multiple servers – There are times one needs to change the IP address of packets coming in the network to direct them to another machine. This mainly happens when you have only one IP address but you need people to get into systems behind the one with the real IP address.
  • It helps in transparent proxying when you need to pretend that each packet passing through your Linux server has the destination on a program on the Linux box itself.

The disadvantages of IP Spoofing are:

  • It is blind to replies – This means that the reply packet from a computer will go back to the spoofed IP address and not the attacker.
  • Serial attack platform – The attacker is able to maintain anonymity by hijacking a chain of attack hosts. The attacker uses point host-the last host in the attack chain to target the victim. Authorities can not trace the attacker’s base host this way.

 7. IP Spoofing Tools 

The common tools used by an attacker for IP Spoofing are:

  • netcommander – This is very easy to use arp tool.
  • Sylkie – This uses neighbor discovery protocol to spoof IPv6 addresses.
  • Aranea – This is another fast and clean spoofing tool.
  • Isr Tunnel – This tool spoofs connections using source-routed packets.

8. Examples Of IP Spoofing Attack

Some major IP spoofing attack examples from real life are:

  • In June 2018 attackers made a two-way attack on American health insurance providers and stole complete human medical records.
  • In 2006 three local banks in Florida were attacked and their internet servers were hacked. The users were redirected to fake login pages and attackers obtained sensitive data of the unsuspecting victims. They got hold of the credit card numbers and PINs of the owners using this attack.

Conclusion

Hope after going through this article you have clarity on what is IP spoofing and how can it be prevented. The history of IP spoofing dates back to the 1980s when it was first discussed in academic circles. In 1989 an article by S.M Bellovin from At&T labs came out which identified the real risks of IP spoofing. IP spoofing is exploiting a trust-based relationship between computers where attackers can personify as another computer to steal sensitive information from a person or organization. Ip Spoofing can be prevented by having proper encryption and authentication tools and methods in place.

So, have you made up your mind to make a career in Cyber Security? Visit our Master Certificate in Cyber Security (Red Team) 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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