Discover the key differences between AWS WAF, ACLs, and Security Groups to protect your cloud applications like a pro!

When it comes to securing your applications and infrastructure on the cloud, there are various tools and services available. AWS offers several security features that can help you protect your resources. I was recently asked by one of my colleagues about what the difference is between AWS WAF vs ACLs vs Security Groups. And here we are!

While these tools all serve the same purpose, there are differences between them that you need to understand to choose the right tool for your needs.

What is AWS WAF?

In the simplest way, AWS WAF (Web Application Firewall) is a Firewall service as the name implies.

It helps protect your web applications from common web exploits that could affect application availability, compromise security, or consume excessive resources. AWS WAF allows you to create rules that block common attack patterns, such as:

• SQL injection

• Cross-site scripting (XSS)

• UDP floods

• SYN floods

• HTTP floods

• Bad bots

• Spoofing

With AWS WAF, you can also protect your APIs from bots and scrapers and can create custom rules or use pre-configured rules to protect your applications.

What is NetworkACL?

Network ACL (Access Control List) is used to filter traffic based on IP addresses or ranges.

ACLs can be applied to individual subnets or network interfaces, and they allow or deny traffic based on the rules you set up. ACLs are commonly used to control traffic in and out of a VPC (Virtual Private Cloud). Besides that, ACLs are stateless. It means they do not keep track of the traffic flow.

What are Security Groups?

Security Groups are also used to control traffic, but they operate at the instance level rather than the subnet level. It is the security level that you encounter after you pass through the NACLs.

Security Groups act as virtual firewalls for your instances, controlling inbound and outbound traffic. Security Groups are stateful, which means they keep track of the traffic flow. This makes them easier to use than ACLs, as you don’t have to worry about setting up separate rules for inbound and outbound traffic.

Differences between AWS WAF, ACLs, and Security Groups

• The main difference between AWS WAF, ACLs, and Security Groups is the level at which they operate. AWS WAF is a service that operates at the application layer, protecting your web applications from common web exploits. ACLs operate at the subnet level, controlling traffic in and out of your VPC based on IP addresses or ranges. Security Groups operate at the instance level, acting as virtual firewalls for your instances and controlling inbound and outbound traffic.

• Another key difference is the type of traffic they filter. AWS WAF is focused on protecting your web applications from common web exploits, such as SQL injection or cross-site scripting. ACLs and Security Groups, on the other hand, are focused on controlling traffic based on IP addresses or ranges.

• Finally, there is a difference in the way they handle the traffic. ACLs are stateless, which means they don’t keep track of the traffic flow. This makes them more difficult to manage than Security Groups. Because Security Groups are stateful and can track the traffic flow. By the way, AWS WAF can also be used in conjunction with Security Groups to provide additional protection for your web applications.

Let me try to provide an analogy to make things clear. Imagine that you are an individual who places a high value on personal security and decides to hire a team of security personnel. For example, you may choose to hire three employees.

• A private guard

• An old security guy in front of your building

• A security desk in front of your home

Your private WAF guardians remain ever-vigilant against potential hazards. They are highly professional and continuously monitor for security risks, always keeping an eye on the bigger picture.

Someone wants to enter the building to see you. They must pass our security personnel, but our ACL security personnel is elderly and cannot remember everyone who comes in or goes out. Also, as you can see, he does not have a desk to write down people’s names. Therefore, he must always check who you are whenever you enter or exit.

Finally, your visitor has arrived at the front door of the building, but there is one more security measure in place — Security Groups. As you can see, this security personnel works indoors and has a desk to keep track of information. Once you inform him of your identity upon entering, he will record it and allow you to exit without asking again. This is because he knows who you are, unlike the ACL security personnel who must check again when you exit the building.

So the image pretty much looks like this:

Summary

In summary, AWS WAF, ACLs, and Security Groups are all important tools for securing your applications and infrastructure on the cloud. While they all serve the same purpose, they operate at different levels and filter different types of traffic. Understanding the differences between these tools is important when choosing the right tool for your needs. By choosing the right tool, you can ensure that your applications and infrastructure are protected from common web exploits and unauthorized access.