A web application firewall (WAF) is instrumental in the protection of web apps through filtering and monitoring HTTP traffic between both the internet and the web app. A WAF protects the latter from various online attacks, especially cross-site forgery, cross-site scripting (XSS), SQL Injection, file inclusion, and the like.
What a WAF is basically, is that it is a protocol layer 7 defense mechanism. It is however not made to defend web apps against various kinds of attacks on its own. Such a method of mitigating attacks is typically part of a wider suite of tools that combined with the WAF creates a holistic defense against an array of attack vectors.
What happens when a web application firewall (WAF) is deployed?
By deploying a WAF with a web application (web app), it is like a shield being placed between the internet and the web app itself. A proxy server protects a client machine’s identity using an intermediary, whereas a WAF works as a reverse proxy of sorts. Meaning, a WAF protects servers from exposure to harmful elements by making clients pass through the firewall before they reach the main server.
Policies help shape the modus operandi of web application firewalls. They aim to protect against vulnerabilities in the web app by filtering out the wrong kind of traffic (malicious traffic that is). Yes, if that traffic is not filtered out then it won’t work.
What value does a WAF hold?
The value of a web application framework (WAF) comes from the speed and the way policy changes are implemented. This gives it the chance to respond quickly to different attack vectors whenever a DDoS attack happens. ALso, limiting the rate of vectors can be implemented quickly through changing WAF policies.
The difference between allowlist and blocklist WAFs – a brief explanation
A web application framework (WAF) operating on the basis of a blocklist protecting against known attacks(negative security model) is known as a blocklist WAF. It can be thought of as a nightclub bouncer denying entry to unwanted and rowdy guests not meeting certain guidelines and criteria.
On the contrary, an allowlist WAF is based on a positive security model allowlist. It only allows pre-approved and pre-recognized traffic. Think of it as security guards at stadiums allowing those fans who have the tickets, have no weapons and are meeting all rules and regulations. If there is a VIP box, then the guards allow those who are on the list.
A fascinating fact: both the allowlist and blocklist WAFs have their merits and demerits. This is the reason a lot of WAFs offer a hybrid security model, implementing the best of both.
Understanding network-based, host-based and cloud-based WAFs
A web application firewall (WAF) can implement in one of three ways which are listed below, with each one having its own advantages and pitfalls.
Network-based web application firewall (WAF)
Network-based WAF is typically based on hardware. As they are locally installed, they cut down latency. Yet they are the most expensive option because they also need storage and maintenance of physical equipment.
Host-based web application firewall (WAF)
A host-based WAF can be integrated completely into an application’s software. Such a solution is affordable in comparison to a network based on and offers a wider degree of customization. Its only pitfall is that it consumes a lot of local server resources, complicated implementation and has high maintenance expenses too.
Such components require a lot of engineering and installation time, are costly, and may also not give affordable anti DDoS protection.
Cloud-based web application firewall (WAF)
This kind of WAF is an affordable option that can be implemented easily. They typically offer a turnkey installation as easy as a change in DNS for redirecting traffic. Cloud-based WAFs have a reduced upfront cost because users either pay monthly or annually for security as a valuable service.
These WAFs can also provide a solution that is consistently updated to protect clients and web apps against the most up-to-date threats, without additional expenses or work on the user’s end. However, its main pitfall is that users often hand over responsibility to a third party, which means that some features of this WAF can be a black box of sorts.