If you run a web application, you are probably familiar with OWASP's top security risks that could affect your web applications. OWASP is short for Open Web Application Security Project. It is a non-profit group created in 2001 to assist website owners and security specialists in protecting online applications against cyber threats.
Over 32,000 volunteers worldwide work for OWASP as researchers and security analysts. A WAF is one of OWASP's recommendations for protecting web applications from risks and attacks. Here's an explanation of what this thing is and why you need it.
In an ideal world, web applications would be able to handle all kinds of attacks and threats. However, in the real world, there are a lot of applications that are not just built properly. Additionally, there are legacy applications that were once secure against threats and attacks but are not anymore because things have progressed. A WAF helps protect web applications from higher layer attacks, i.e., attacks that pass through a standard network firewall undetected.
It comes in handy, especially if you have various web applications and can't tweak every single one to handle higher-layer attacks. Shielding your web/applications with a WAF is an easy way to prevent attacks against all of them without having to modify and configure them separately.
What Does WAF Stand for?
WAF is short for web application firewall. Simply put, it's a security solution that intercepts and examines HTTP traffic between the internet and a web application, keeping out threats. Typically, it defends web applications against threats like cross-site scripting (XSS), cross-site forgery, file inclusion, and SQL injection.
However, a WAF is not made to withstand all kinds of attacks; it operates at protocol layer 7 and is usually a part of a suite of tools that together form comprehensive protection against various attack vectors.
How Does a WAF Work?
A WAF is a shield installed in front of one or more web applications and the internet. By requiring clients to travel through the WAF before contacting the server, the WAF thus performs the function of a reverse proxy, preventing the server from being exposed to malicious clients.
WAFs can execute as server plugins, network appliances, or cloud services, intercepting and examining data packets to and from a web application to block attacks and threats based on pre-loaded security rules. WAF security differs from a proxy server, which uses an intermediary to protect the identity of a client machine.
The pre-loaded security rules that WAFs operate on are often referred to as policies. These policies shield the application from vulnerabilities by screening out malicious traffic. It follows that a WAF can be created to function using a negative security model, i.e., denying access to clients who are listed on a blocklist, or a positive security model, i.e., granting admissions only to pre-approved (allowlist) clients. Because both allowlists and blocklists have benefits and downsides, many WAFs provide a hybrid security approach that combines the two.
A WAF's value stems partly from how quickly and easily policy changes can be made, enabling faster reaction to various attack vectors. For example, during a DDoS attack, changing WAF policies immediately facilitates rate limiting.
Why WAF Is Important
A rising number of businesses, such as social networking service providers, digital banks, and developers of mobile applications, are realizing the value of WAFs. WAF benefits include:
Keeping data safe
Organizations typically store a large portion of their sensitive information (customer records, payment information, etc.) in a core database as a means of data protection. The core database can then be accessed via web applications. Organizations also use IoT devices and mobile apps to streamline business interactions more frequently.
Numerous online transactions take place at the application layer. For access to this information, attackers frequently target web applications. However, putting a firewall in front of web applications helps keep information safe.
Ensuring PCI DSS compliance
The Payment Card Industry Data Security Standard i.e., PCI DSS, requires the establishment of a firewall by any entity managing cardholder information. This is one compliance standard that can be met with the use of a WAF. Therefore, a WAF is a crucial part of a company's information security paradigm.
Part of a comprehensive security strategy.
To establish an in-depth information security model, WAF technology can be used together with additional security measures like standard firewalls, intrusion detection systems, and intrusion prevention systems.
What Are the WAF Characteristics?
As already mentioned, WAF technology can be host-based, cloud-based, or network-based, and is typically deployed through reverse proxies and placed in front of a web application. Network-based WAFs are hardware-based and installed to reduce latency. In contrast, host-based WAFs can be fully incorporated into an app's software and are far less expensive to do so. They also make it easy to customize the firewall. Meanwhile, cloud-based WAFs are often marketed as a security-as-a-service subscription and are managed and updated by the service provider.
Although cloud-based WAFs offer pre-set security rules, organizations can design their own security policies and rules to suit their specific application logic. All in all, typical features of a WAF network include:
Known attacks repositories
Attack signatures are recurring patterns in web traffic that can point to malicious activity. These patterns include request types, odd server responses, and recognized malicious IP addresses.
Earlier WAFs relied heavily on known attack repositories, which were less efficient against fresh or undiscovered attacks. However, WAF security has advanced beyond identifying known malicious attacks thanks to AI software, as will be discussed below.
AI-driven traffic behavior analysis
Thanks to AI technology, behavioral analysis can be performed on traffic based on established behavioral benchmarks for different types of traffic to find anomalies that point to an attack. By doing so, assaults that don't follow well-known malicious patterns are brought to light.
Application profiling
This entails looking into an application's architecture, including the common queries, URLs, responses, and allowed data types. This makes it possible for the WAF to recognize and deny untrusted requests.
Customization
WAF allows operators to set the security guidelines that apply to web traffic. As a result, enterprises can tailor WAF behavior to their own requirements and stop the blockage of non-threatening traffic.
Correlation tools
These examine incoming traffic and classify it using application profiling, set rules, artificial intelligence, and known threat signatures to determine what to block and allow.
DDoS mitigation tools
A cloud-based infrastructure that defends against DDoS assaults can be integrated into WAF technology. The DDoS defence system, which can handle large attacks, can be activated immediately if a WAF network senses DDoS attacks.
Content delivery network
A cloud-based WAF can offer a CDN to archive the website and reduce load times since WAFs are implemented at the edge of the network. WAFS can distribute CDN on several geographically dispersed points of presence (PoPs), allowing users to receive services from their nearest PoP.
Conclusion
Web applications are vulnerable to various kinds of attacks, not just at the network and transport layer but at the application layer too. While standard network firewalls do their best to prevent attacks at layers 3 and 4, a web application firewall is necessary to prevent attacks at the higher layers.
WAFs can help with HTTP flood attacks, slow loris attacks, and OWASP top 10 attacks that would otherwise overwhelm standard network firewalls. WAF technology can be deployed on the cloud, network, or installed on the host. You can always get the help of web security experts to determine which WAF and deployment mode is right for you.