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IP spoofing: What it’s all about and how to protect yourself 

Hackers often use IP spoofing — a specific type of cyberattack — to gain unauthorized access to systems. This method spoofs the sender’s IP address so it appears to users that the IP packet is coming from a legitimate source. Read on to learn more about IP spoofing and how it works. Also discover how to protect yourself from IP spoofing and how Avira Phantom VPN can help ensure your identity remains anonymous. 


What is IP spoofing? 

Internet-enabled devices and websites communicate with each other using TCP/IP (transmission control protocol/internet protocol) addresses. They provide information about the host or a network interface and its location, enabling them to be uniquely identified. In this regard, a distinction is made between private and public IP addresses. 

In the case of IP spoofing — a subtype of spoofing — hackers create IP packets with fake sender IP addresses to impersonate — or spoof — another computer system. This is how cybercriminals gain access to systems. Once in, they can steal data, infect computers with malware, or cause entire servers to crash. 

How does IP spoofing work? 

Data is first divided into packets so it can be transmitted over the internet. These packets are transmitted independently of each other from the sender to the recipient. Only at the end are they reassembled. Every packet has what’s referred to as an IP header. This contains information about the packet such as the source and destination IP address. 

Hackers use IP spoofing tools that change the source address in the packet header, making it appear to the receiving system as if the packet came from a trustworthy source — such as a computer on a legitimate, internal network. The system then accepts the packet and hackers gain access to the system. Since IP spoofing occurs at the network level, there are no external signs of tampering. 

Types of IP spoofing 

Hackers often use IP spoofing as a tool to commit online scams such as identity theft — with the ultimate aim also being to shut down company websites or servers. Here are some of the most common forms: 

  • DDoS attacks: Distributed denial of service attacks — or DDoS attacks for short — refer to a technique where hackers use spoofed IP addresses to flood computer servers with data packets, overwhelming the website or network and causing it to crash. Cybercriminals also use the spoof IP address to conceal their identity during DDoS attacks. 
  • Botnet masking: Attackers also use IP spoofing to gain access to devices via masked botnets. Botnets are networks of computers controlled by a single botmaster. The networks consist of individual bots that sniff data on the target device or cause other damage. With the help of IP spoofing the bots are assigned a fake IP address, making them more difficult to detect. 
  • Man-in-the-middle attacks: Another IP spoofing method is a man-in-the-middle attack. With these types of attack, cybercriminals interrupt the communication between two devices and change the IP packets that arrive at the recipient — without the original sender’s knowledge. This allows hackers to read, intercept, or tamper with data traffic between two people. Attackers often sell the confidential information they’ve sniffed or use it for further cyberattacks. 
  • Non-blind spoofing attacks: With this type of spoofing attack, the attacker is on the same subnet as their target. Using what’s known as a session hijacking technique, the hacker can corrupt the data stream of an established connection and then build a connection to the attacked computer. This allows attackers to bypass IP-based authentication. 
  • Blind spoofing attacks: In contrast to non-blind spoofing, with blind spoofing the attacker is outside the internal network. The attacker sends packets to the target machine to sample sequence numbers from the acknowledgment and to predict future sequence numbers. These help to bypass authentication means such as various log-in methods. However, this type of attack is now more complex for cybercriminals and is therefore becoming less common. 

IP spoofing attacks often go unnoticed for ages, giving cybercriminals the opportunity to cause more damage. With Avira Free Security, you can suss out hackers more quickly and make your surfing experience more secure. 


How do you detect IP spoofing? 

The sneakiest thing about IP spoofing is that it’s difficult for end users to detect. That’s because these attacks take place on the network, meaning spoofed external connection requests usually appear legitimate with no external signs of tampering. 

However, network monitoring tools are available that can detect IP spoofing. With them, companies can analyze traffic at the endpoints. A common method used for this is packet filter systems. These are often built into routers or firewalls and detect inconsistencies in traffic between the sender and recipient’s IP packets. 

Types of packet filtering 

There are two main types of packet filtering: Ingress and egress filtering. Here’s how they work: 

  • Ingress filtering: Ingress filtering checks incoming IP packets to see whether the source IP header matches a valid source address. Packets that appear suspicious are rejected. 
  • Egress filtering: The counterpart to ingress filtering is egress filtering, where the outgoing packets are checked. If the IP source address doesn’t match that of the company’s own network, it’s not sent. This is intended to prevent IP spoofing attacks by insiders. 

These are all techniques for IT specialists to detect IP spoofing. But how can general users protect themselves from this type of cyberattack? Let’s find out below. 

How can you protect yourself against IP spoofing attacks? 

Although you can’t defend yourself entirely from IP spoofing attacks, you can increase your security on the internet by taking a few preventative steps. These include: 

  • Set up your home network correctly: When you set up your home network, change your router’s default username and password. You should at least set a new password that consists of at least 12 characters containing a mix of uppercase and lowercase letters as well as numbers and special characters. 
  • Suss out phishing attempts: With phishing attacks — a form of email spoofing — cybercriminals will email you in an attempt to trick you into revealing your password or other sensitive information. It often seems as if the email came from a reputable sender address. However, if you click any links or open infected attachments, the attackers will gain access to your computer. They can also launch other attacks from your email address. So, always be vigilant and always check whether the message comes from a trustworthy source. 
  • Check website security: Websites without a current SSL certificate are more vulnerable to hacker attacks. Exchanging sensitive data with such websites poses a security risk, so avoid them if possible. You can tell a site is unsafe as the URL will start with HTTP. Websites whose URLs start with HTTPS and have a padlock symbol in the URL bar are safer. 
  • Use an antivirus tool: An antivirus program is a solution that allows you to scan your PC for malware. You should scan your device regularly and keep your software up to date to stay safer from the latest online threats. 
  • Use a VPN: Public networks, such as hotspots, are usually unsecured. This makes it easy for hackers to access the devices that are connected to them. To protect your sensitive data when surfing in public spaces, you should use a VPN (virtual private network). It encrypts your internet connection, so you send and receive data more securely. 

Avira Phantom VPN encrypts your traffic by assigning you a different IP address which cannot be traced back to you. A VPN routes your internet activity through a super secure tunnel that neither hackers nor other third parties can access. This makes it more difficult for cybercriminals to view your traffic and tamper with your IP address or that of your target machine. You then get to surf anonymously and more securely. 


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Surf anonymously with Avira Phantom VPN and improve your protection against IP spoofing attacks.

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Surf anonymously with Avira Phantom VPN and improve your protection against IP spoofing attacks.

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