Understanding Teardrop Attacks to Prevent DDoS Incidents

Denial-of-service attacks can come in a variety of different forms, and understanding the different types of cybersecurity threats that your business faces is the first step to safeguarding against them. One such DoS attack that can bring an operating system to a disruptive halt is a teardrop attack.

In this guide, we’ll cover everything you need to know about this type of cyberattack, including how teardrop attacks work, the role they play in denial-of-service campaigns, and the best practices for detecting and preventing them.

What is a teardrop attack?

A teardrop attack is a type of Denial-of-Service (DoS) attack that exploits a vulnerability in the way some operating systems handle fragmented Internet Control Message Protocol (ICMP) packets. This type of IP fragmentation attack involves sending fragmented IP packets with overlapping, invalid offsets to a target system, ultimately leading to a system crash (or otherwise causing the system to become unresponsive). Like all DoS attacks, the purpose of a teardrop attack is to disrupt the organization’s operations, sometimes with the aim of extorting a ransom and sometimes for no other purpose than to cause the organization harm.

In the context of DDoS

Teardrop attacks and distributed denial-of-service (DDoS) attacks both fall under the broader category of DoS attacks. A teardrop attack works by exploiting a specific vulnerability related to fragmented ICMP packets, while DDoS attacks involve flooding a target with a high volume of traffic from multiple sources. In both cases, however, the end goal is to disrupt the target system.

In some cases, hackers will use a blend of teardrop attacks and DDoS attacks to create a more sophisticated assault. To protect your website against these threats, it’s important to create a cybersecurity plan that is designed to safeguard against these attacks in all their various forms.

How they work

Teardrop attacks use IP fragmentation to target a vulnerability that is present in some versions of the Microsoft Windows operating system and certain Linux-based systems. When data is sent over the internet, it is divided into smaller units called data packets. These packets are transmitted individually and reassembled at their destination. Sometimes, a large packet may be fragmented into smaller fragments before transmission. Each packet contains a “fragment offset” field in its IP header. This field indicates the position of the fragment within the original, larger packet to help the receiving system to reassemble the fragments in the correct order.

In a teardrop attack, a hacker sends a series of IP packets with deliberately manipulated or overlapping fragment offset fields. When the target system attempts to reassemble the fragmented packets, it may encounter errors due to the manipulated fragment offsets. This can cause the system to crash, become unresponsive, or experience other adverse effects.

How to detect and prevent them

DoS attacks such as teardrop attacks can often be challenging to identify and even more challenging to prevent. If you would like to keep your computer systems and web applications from this potentially crippling form of DoS attacks, here are some of the signs, tools, and best practices you need to be aware of.

Common signs and symptoms

The first step to preventing teardrop attacks is knowing how to detect them. While there are several tools and techniques that can be used to identify teardrop attacks, knowing the common signs and symptoms of these attacks is key as well.

Some of the common signs that your company is the target of a teardrop attack include:

• Network degradation or outages: Teardrop attacks can lead to network congestion and sluggish performance. In severe cases, they may cause network outages, making it difficult for legitimate users to access resources.
• Unusual log entries: Keep an eye on system logs for a surge in fragmented packets or unusual patterns in fragment offset values, as these can potentially be a sign of a teardrop attack.
• System instability or crashes: Teardrop attacks can cause target systems to become unstable, leading to crashes or unresponsiveness. If your computer system is frequently crashing or experiencing instability then this is something that warrants further investigation.

Tools and techniques for identification

Along with understanding what a teardrop attack looks like, there are numerous tools and processes you can implement for swift identification of these attacks. A few effective tools and techniques to consider include:

• Packet sniffers: Network administrators can use packet sniffing tools to capture and analyze network traffic. These tools are able to identify anomalous patterns in the fragmentation headers that could indicate a teardrop attack (such as overlapping or conflicting fragment offset values).
• Intrusion detection systems (IDS): IDS systems can be configured to detect patterns indicative of teardrop attacks and can provide real-time alerts or log entries when suspicious activity is detected.
• Network monitoring tools: Network monitoring solutions can be used to track packet behavior and flag any unusual patterns that need to be investigated.

Network security measures

The ability to swiftly detect teardrop attacks is key when it comes to mitigating their damage, but there are also network security measures you can implement to prevent teardrop attacks outright. This includes network security measures such as:

• Firewalls: Network firewalls can be configured to filter and block suspicious or malformed packets, including packets with malformed fragment offset values.
• Ingress and egress filtering: Implement strict ingress and egress filtering rules to prevent packets with abnormal or conflicting fragment offset values from entering or leaving the network.
• Update and patch systems: Keep all operating systems and network devices up to date with the latest security patches. This helps ensure that known vulnerabilities, including those exploited by teardrop attacks, are addressed.

Security software and solutions

Along with network security solutions, here are some other security solutions that can be helpful for protecting against teardrop attacks:

• Intrusion prevention systems (IPS): IPS solutions actively monitor network traffic for suspicious activity and can automatically take action to block potential teardrop attacks.
• Anti-malware software: While not specific to teardrop attacks, robust anti-malware solutions can help identify and prevent various types of attacks, including those involving malicious network traffic.
• Security audits and penetration testing: Regularly conduct security audits and penetration tests to identify vulnerabilities in your network. This proactive approach helps discover potential weak points before they can be exploited.

Best practices for mitigation

Once you have identified that your company is the target of a teardrop attack, every second counts. To mitigate the damage that these attacks can potentially cause, it’s vital to have a thorough plan in place ahead of time for how your company will respond.

Best practices for mitigating the impact of teardrop attacks can include things like isolating the affected system, implementing traffic filtering rules to block the attack traffic, and notifying security teams to respond to the incident. You will also want to have a plan in place for how your company will respond to DoS incidents that cover considerations such as communication protocols, business continuity, customer communication and support, and post-incident analysis.

Lastly, it’s a good idea to promote DoS and DDoS awareness and training throughout your organization. Make sure that everyone understands what these attacks are and the role they play in preventing/mitigating them to ensure a seamless and coordinated response to DoS incidents.

Get peace of mind from DDoS attacks with SiteLock

DoS and DDoS attacks — in all of their various forms — are a serious security threat for companies of all sizes. Thankfully, these attacks can largely be prevented with the right cybersecurity solutions.

With SiteLock, you get access to a comprehensive suite of security solutions designed to protect your website against cybersecurity threats. From malware removal to web application firewalls (WAFs), SiteLock provides every solution modern businesses need to ensure peace of mind from cyberattacks.