Smurf Attack 101: A complete Guide to Protecting Your Network in 2023

With every passing day, the cyber world is making more and more progress regarding the development of secure browsing techniques. However, it seems like cybercriminals also work just as hard to come up with new ways to attack networks and exploit vulnerabilities. 

One such threat is the Smurf attack! This type of attack can cause some serious damage to your network if you don’t take measures to effectively prevent it. We shall discuss everything you need to know to protect your network against a Smurf attack. Let’s get started:

What is a Smurf attack?

A Smurf attack is a type of denial of service (DDoS) attack in which the attacker floods the target network server to render it useless. It originates in the network layer and uses two major components: Internet control message protocol (ICMP) and Internet protocol (IP) broadcast addressing. They are exploited by the attacker to overwhelm a network and crumble its defenses.

To summarize, it sends ICMP requests using the victim’s IP address. And as soon as the hosts receive these spoof requests, they respond to the target or victim system. This can render the application to be completely inaccessible due to the large number of requests. 

Source: Imperva

The Smurf Attack – A brief history in Time

The name Smurf may remind you of those adorable blue cartoon characters, however, this particular attack has more severe consequences than the regular Smurf mischief. 

The Smurf attack first came around in 1997 when a popular hacker, Dan Moschuk, published a Smurf.c file. This particular malware took down multiple IRC servers with its flood attacks. Dan, who also went by the alias TFreak, later also created a UDP version for the Smurf attack and named it Fraggle.c. 

1997: Tfreak (Dan Moschuk) published smurf.c since he'd learned it had already been widely circulated. This was perhaps the first DDoS attack tool. https://t.co/tMBroJ1l2q pic.twitter.com/IQO81LQ0Hi

— Today In Infosec (@todayininfosec) October 12, 2019

This particular piece of malware reshaped the way network devices were made. Manufacturers even disabled IP broadcast addressing by default and the feature was only restricted to LAN.

How does a Smurf attack work?

Simply put, a Smurf attack floods the target network with ICMP request (ping) packets which are sent to various hosts using IP broadcast addressing. This increases the volume of traffic and overwhelms the network servers into crashing. 

And while these attacks are nothing like their cartoon counterparts, it might help you visualize the unending request chain:

Source: Giphy

Here is a brief outline to help you better understand it’s timeline:

1. Spoofing: After the attacker targets a network, they spoof the IP address of the packets so that they match the victim’s IP address. 
2. ICMP requests: The attacker then sends multiple ICMP request (ping) packets to various hosts using IP broadcast addresses [help to send a message to multiple devices simultaneously within a network].
3. Hosts receive pings: The devices receive the ping and respond with ICMP echo replies.
4. Hosts flood target network: The ICMP replies are all sent to the victim network because the attacker has spoofed its IP address.
5. The attack is successful: The target network gets flooded and the network traffic overwhelms the resources. The target network, thus, becomes unresponsive or crashes under the load. 

What are the different types of Smurf attacks?

Here are the two main types:

Basic Smurf Attack

In a basic Smurf attack, the attacker targets the victim network and sends ICMP requests (ping) packets that have the victim’s IP address. The packets are sent to the network’s broadcast address. When the hosts reply to these pings, they overwhelm the victim servers and can lead to the target network becoming unresponsive.

Advanced Smurf Attack

Techniques like the Smurf amplification attack and distributed Smurf attack can be classified as more advanced versions of the basic Smurf attack. Using these new mechanisms, attackers can target multiple victims simultaneously and can even take down more complex and extensive networks.

Smurf attack transmission and effects

Emails and links infected with Smurf Trojans may end up in a user’s inbox from time to time. And no matter how good the discount looks or how authentic the email looks, you must never click on suspicious links. Downloading software or applications using such emails can transmit the Smurf Trojan into your system, where it will remain hidden till it is activated by the attacker. 

A Smurf attack may also be bundled in some rootkit and helps the cyber attacker create backdoors to gain unauthorized access to the victim’s system and data.

Source: Wikimedia

A Smurf attack can damage your business in various ways. It cripples company servers and renders the service to be completely unavailable, which can cost you revenue and customer satisfaction.

This DDoS attack can also lead to a data breach where you may end up losing your application resources, operational information, and customer data. Therefore, you must take multiple security measures to help protect your network and use effective monitoring techniques while you are at it!

Top 11 security tips for Smurf attack prevention- How to protect your network against them?

Since a Smurf attack can cause some real damage to your network and systems, it is much more convenient to avoid it. Here are some of our best tips and tricks to help protect your systems and business against a Smurf attack: 

1. Disable IP-directed broadcast at the network perimeter to prevent attackers from using IP broadcast addressing for amplification/ smurf attacks.
2. You can apply ingress filtering on devices and drop packets that have spoofed source IP addresses.
3. Configure access control lists (ACLs) to monitor and control access to your network and limit the number of ICMP requests that can enter your network.
4. Avoid clicking on random email links or downloading suspicious software without verifying the source. 
5. Use effective techniques to monitor unusual traffic spikes, packet volume, etc, and alert any suspicious activity.
6. Set up efficient alerting mechanisms to take prompt action.
7. Use intrusion detection/prevention systems (IDS/IPS) to detect and block Smurf attacks in real-time.
8. Use a reliable VPN service, like PureVPN, to encrypt your traffic and pass it through a secure network tunnel.
9. Use other DDoS mitigation techniques and tools.
10. Make sure to regularly update your system applications and software and keep the system up-to-date with the latest bug fixes and patches. 
11. Educate employees regarding phishing emails, DDoS attacks, etc.

Try a better way to be anonymous with PureVPN

You can use a reliable VPN service, like PureVPN, to help prevent a Smurf attack. PureVPN helps you effectively encrypt your network traffic so that it cannot be intercepted by an attacker. This is crucial when it comes to a Smurf attack because it can help prevent ICMP packet manipulation.

Further, your IP address remains safe from getting spoofed by the attacker as it originates from the VPN server. PureVPN can also help you with IP whitelisting, network isolation, and traffic encryption to equip you against it. 

And the best part is that your systems can enjoy complete anonymity on the internet by masking their IP address and get exclusive access to regional deals and discounts as well. 

• Remain anonymous online and hide your IP address with PureVPN.
• Securely host private servers with our Dedicated IP address.
• Get global connectivity with PureVPN’s extensive server of 6500+ servers in 70+ locations.
• Enjoy PureVPN’s DNS leak protection feature.
• Encrypt your network traffic and operate safely with advanced AES 256-bit encryption.

To wrap up

While it may not be possible to completely prevent a Smurf attack, you can always work towards it to soften the blow. This DDoS attack, like many others, can cause serious damage to your systems and business operations which is why you must always remain vigilant and take necessary precautions to minimize these damages. 

Disabling IP broadcasting is crucial to protect your network. However, you can also take other measures, like detection and prevention systems,  ACL configuration, traffic monitoring, ingress filtering, etc. A reliable VPN, like PureVPN, can also help you equip yourself against these attacks and encrypt your network for a more secure experience. 

Frequently Asked Questions