Web Application Vulnerability Scanners – The Quick Guide

Web Application Vulnerability Scanners – The Quick Guide

Web Application Vulnerability Scanners
Web Application Vulnerability Scanners | Image by Bruno /Germany from Pixabay

Web application vulnerability scanning is widely recognized as the most effective way to check your website for a huge list of known vulnerabilities – and identify potential vulnerabilities in your application security. The vulnerability assessment can be used as part of a stand-alone assessment or as part of a comprehensive strategy for continuous security monitoring.

What is a Web Vulnerability Scanner?

Vulnerability scanners are automated tools that scan web applications for security vulnerabilities. Better performing scanners can potentially deepen an application using more advanced techniques. Pioneering application systems testing techniques mean that Burp Scanner, the engine for the Burp Suite’s application security testing products, can identify vulnerabilities that many other scanners would miss, including asynchronous SQL injection and SSRF.blind for example.

A web application security scanner, also known as a web application security scanner, is an automated security tool. It scans web applications for malware, vulnerabilities and logical errors. Vulnerability scanners for web applications use black-box tests because these tests do not require access to the source code, but instead launch external attacks to test for security vulnerabilities. These simulated attacks can detect path trespassing, cross-site scripting (XSS) and command injection.

Vulnerability scanners for web applications are categorized as Dynamic Application Security Testing (DAST) tools. There are several commercial and open-source scanners on the market. Each is designed to automate security tasks, reduce security costs, and increase security coverage.

How does a web vulnerability scanner work?

Web vulnerability scanners work by automating multiple processes. This includes crawling and crawling applications, identifying standard and general content, and finding general vulnerabilities.

There are two main approaches to vulnerability analysis: passive and active. A passive scan is a non-intrusive scan that simply examines items to see if they are vulnerable. You can think of this method by imagining hitting a door but not touching it to see if it is open or locked. If the door is closed, that means the end of this branch of your investigation.

An active scan, on the other hand, is a simulated attack on your website to access vulnerabilities as they appear to a stranger. If you think of it as a door, the fact that it could be closed wouldn’t be a dead end. Instead, your investigation would lead you to test the door, maybe pick the lock, or even force entry.

Some types of scanning also involve authentication, where the scanner uses access permissions to determine if there are other open or closed “doors” in the application. Some scanners can purchase these permissions themselves; others require them before testing.

The scanner then produces a more or less detailed report depending on the type of analysis carried out. This report usually includes the specific query and response that the application used to diagnose each reported vulnerability so that an informed user can manually investigate and confirm the existence of the bug.

How web vulnerability scanner can help map an application?

Some scanners automate site mapping in part using spidering. More modern scanners use exploration – the scanner describing all possible paths a user could take and how their journey would be affected by links and other navigational transitions.

Modern applications contain many states. For example, on an e-commerce site, there might be a page that shows your “shopping cart” – this page can be almost identical whether or not you have anything in that “shopping cart”, except for a “payment” – Buttons. The iteration of the page containing a “checkout” button or “shopping cart” item is a separate state for the scanner to consider.

What are the most common vulnerabilities detected by the automated scan?

Some scanners can detect a wider range of vulnerabilities, such as when their logic is updated more frequently. Regular updates can play a big role in maintaining your security status – as soon as a vulnerability becomes public, it is also public to hackers. You should take this into account when choosing your vulnerability scanning tool.

Some of the security gaps that are reliably detected by ordinary scanners include:

  • Reflective Cross-Site Script (XSS)

Automated scanners typically send test strings with HTML markup and look for answers for those strings so that they can identify basic XSS vulnerabilities.

High-performance scanners typically give you customization options at various stages of your scan, including scan configuration, target area, vulnerabilities to assess, and details of reports generated after the scan.

  • Directory traversal

Some path traversal vulnerabilities can be detected by sending a traversal sequence that targets a known file and looking for the response for that file to appear.

  • SQL injection

In this way, an attacker could intervene in the requests that an application makes on its database. This can sometimes be detected by using basic payloads that produce noticeable error messages.

  • Simple directory entries

This type of vulnerability can be identified by asking for the directory path and looking for an answer that has text that looks like a directory listing.

  • Some command injection security vulnerabilities

These types of vulnerabilities can often be detected by inserting a command that causes a delay or returns a specific string in the application response.

  • Open forwarding

A scanner tests for these vulnerabilities by submitting payloads to test whether a setting can cause a redirection to any external domain.


Automated scanners typically rely on a single methodology for application security testing – this is one reason for the high number of false positives produced by some scanners. Burp Scanner uses a diverse arsenal of techniques to create a more complete image. This unique blend of AST techniques maximizes coverage while generating minimal false positives.

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