This post is part of a series about Layer 3, Layer 4, and Layer 7 DDoS attacks.
What makes Layer 3 DDoS attacks so disruptive to network infrastructure? How do attackers use massive volumes of traffic to take down entire systems? How do they hide their identity during these attacks? And what strategies can companies use to defend themselves?
Recent DDoS threat reports point to a significant surge of DDoS attacks in 2024. Layer 3 DDoS attacks are a type of DDoS attack, which targets the network layer in the Open Systems Interconnection (OSI) model.
Layer 3 of the OSI Model: One of the Key Targets for DDoS Attacks
The strength of this type of attack lies in its ability to congest the network itself; Layer 3 attacks make it challenging for businesses or critical infrastructure to maintain online services during an attack.
Let’s have a closer look at what this method of DDoS attack entails.
Exploiting Protocols that are Key to Network Functioning
Layer 3 DDoS attacks typically exploit protocols that are essential to the normal functioning of a network, such as Internet Protocol (IP) and Internet Control Message Protocol (ICMP). These protocols are designed to handle requests efficiently – but they can be abused.
Packet Spoofing and Amplification
Attackers often use IP spoofing, where the source IP addresses of the attack packets are faked. This makes it difficult for the network to block malicious traffic based on IP and complicates tracing the origin of the attack.
In some cases, the attack is amplified by leveraging other devices or networks (called amplifiers or reflectors). For example, an attacker might send a small request to an external server, causing that server to respond with a much larger reply to the target, amplifying the amount of traffic sent.
Volumetric Attacks that May Use Botnets
Layer 3 DDoS attacks are typically volumetric, meaning they aim to overwhelm the target by consuming as much of its available network bandwidth as possible.
In many cases, attackers use botnets—large networks of compromised devices—to send vast amounts of traffic simultaneously. By doing this, the attacker can generate traffic levels that far exceed the capacity of the target’s network.
Router and Firewall Overload
Since Layer 3 attacks focus on the network layer, they can directly impact routers, firewalls, and other networking equipment. These devices are responsible for handling and routing traffic, and they have a finite capacity for managing packet flows.
A Layer 3 attack sends enough packets to exhaust the processing capacity of these devices, causing legitimate traffic to be dropped or delayed.
Targeting the Bandwidth
Layer 3 DDoS attacks typically aim to saturate the target’s internet bandwidth. By sending huge volumes of traffic, the attacker ensures that there is no available bandwidth left for legitimate requests.
This is especially effective when targeting organizations with limited bandwidth or inadequate network defenses.
The Most Common Types of Layer 3 DDoS Attacks
The most common types of Layer 3 attacks include:
- ICMP Floods (Ping Floods): Attackers send a flood of ICMP echo requests (ping requests) to a target. The network devices must process each request and send a response. In large volumes, this exhausts the target’s processing power and bandwidth, rendering it unable to respond to legitimate traffic.
- IP Fragmented Floods: IP Fragmented Flood is a DDoS attack aimed at consuming computing power and saturating bandwidth. They may also crash devices in rare cases because of buggy packet parsing. IP Fragmented Floods are generally spoofed attacks and normally come at a very high rate and in most cases have no identifiable Layer 4 protocol – but just garbage; and the packets have to be reassembled by various devices along the way. Generally, this flood is used as a basic but effective flood to bring down perimeter devices or saturate bandwidth. IP fragmentation is the process of breaking up a single Internet Protocol (IP) packet into multiple packets of a smaller size.
How Do Layer 3 Attacks Impact the Network?
When a Layer 3 DDoS attack is successful, the network infrastructure either slows down or becomes entirely unavailable. Routers, firewalls, and switches can crash or become unresponsive. The target’s network can become isolated from the internet due to complete bandwidth exhaustion.
How to Mitigate Layer 3 DDoS Attacks
Methods of mitigating Layer 3 DDoS attacks include:
- Rate Limiting: Limiting the number of ICMP or UDP packets a network can process within a certain timeframe helps mitigate some forms of Layer 3 DDoS attacks.
- Traffic Filtering: Firewalls and Intrusion Prevention Systems (IPS) can be configured to detect and drop malformed packets or traffic that appears suspicious (e.g., IP spoofing).
- Blackholing: In severe cases, administrators may route all incoming traffic to a null route (blackhole) to protect the network from being overwhelmed, though this can lead to temporary service outages.
- Scrubbing Centers: Specialized DDoS protection services can reroute traffic through scrubbing centers that filter out malicious traffic before sending legitimate traffic back to the target.
Leveraging Continuous DDoS Vulnerability Testing
The only way a DDoS attack can succeed is via the vulnerabilities or misconfigurations of your DDoS protection solutions. To avoid the potential risk of Layer 3, 4, and 7 DDoS attacks, maintaining ongoing, automated DDoS testing is key.
MazeBolt’s RADAR™ solution provides organizations with the required insights to identify DDoS vulnerabilities, for your specific environments, continuously and automatically, without any downtime. With RADAR, you can mitigate the risk posed by all types of DDoS attack, and maintain the business continuity of critical online services.
To learn more about DDoS Vulnerability Management, speak with a MazeBolt expert.
