March 2nd, 2022 By The Guide

DAST and Modern Software Development

DAST stands for Dynamic Application Security Testing and is a relatively new approach towards security testing for your apps. In brief, DAST is used to discover vulnerabilities in your software by attacking it through the front-end, as opposed to writing tests that are run internally against your application.

There are a range of benefits and a few drawbacks to using DAST for your security and penetration testing needs, but despite this, DAST too often remains overlooked in the industry due to the complexity involved in implementing it. However, the benefits you reap overshadow the implementation effort needed plus Guide-Rails® can simplify the setup. Read on to learn more.

What is DAST?

As many developers and testers are well aware, security and penetration testing are a never-ending game of cat and mouse between blackhats and whitehats. It’s simply a fact that unknown security vulnerabilities lie waiting in many widely used apps and many blackhats will take full advantage of any zero-day exploits, so it behooves testers to be as thorough as possible when attempting to discover and locate these issues before the bad guys do.

Much of traditional application testing typically involves attacking an application from the back-end or by running tests against the app’s code. Penetration testing generally involves a wider scope of test types, from social engineering to exploiting network vulnerabilities and sometimes even attempting to breach physical security measures at data centers. What sets DAST apart is its focus on attacking an application through the front-end, mimicking the behavior of a malicious user.


One of the biggest pros of DAST is that you don’t need access to the source code. Though this may not sound like an advantage, it allows you to more accurately simulate real-world attacks, discover vulnerabilities and identify likely points of ingress as real malicious users would. It is independent of the application, so DASTs are very flexible and can be run against many different types of projects.

It identifies immediate threats in your software that are potentially exploitable by malicious users, both in the form of code malfunctions and also improper software/server configuration. DAST also helps you to spot runtime issues that are difficult to catch during static code analysis. DAST helps to test and discover exploits lurking in places such as RAM usage, memory allocation, and related exploits that are difficult to discover otherwise. Static code analysis does not help with this and simulating or mocking these conditions in a way that accurately reflects real world loads and use cases is difficult to do.


DAST is not without its drawbacks. While it is a good tool for discovering unknown exploits in the front end without requiring access to the code, this also means that when an exploit is discovered, it can be difficult to track down the exact source of the issue. DAST can only tell you that an issue exists and demonstrate how it can be exploited through the front end, but locating the actual source of the error in the code is left to testers and developers. It’s highly bug and project dependent as to how much of an issue this is – sometimes, the link between the front-end exploit and the back-end code is very obvious, but sometimes it is not at all obvious and DAST is unable to help with more extensive debugging.

DAST is also relatively slow compared to other common types of testing. This is in part due to the nature of it – DAST scanners start by crawling the entire application through the front-end to check for entry points and potential exploits. After identification, these entry points then have a battery of tests run at them to check for exploits. Depending on the size of the application being tested, this can take on the scale of days to run.

Why is DAST Important? 

DAST is important because it seeks to find and exploit issues that already exist in your application. It requires some security expertise to know where exploits are most likely to lie and what kind of exploits they are vulnerable to (SQL injection, code injection, cross-site scripting, session hijacking, etc.) in order to test for them. However, these kinds of exploits represent significant security issues that can have significant consequences for any business that falls for such an attack. Not only will such a business suffer a reputation loss, but with more stringent regulations surrounding data breaches, there is also the potential for significant fines from regulators as well.

How DAST Tools Enhance Web Application Security 

DAST helps to enhance web app security in a number of ways. Besides the aforementioned ability to discover unknown exploits in existing code, it can also test for a range of potential issues that is difficult to test for with other testing types, such as static analysis. An example of this is testing for permission or access role exploitation. This is when a user is able to access or make use of information that they should not be able to as defined by their access permissions. This is not possible to check with static code analysis, but it’s a great use of DAST. This is particularly useful for API endpoints, where throttling, rate limits and access limitations are common.

Another example of how DAST enhances security is by testing vulnerabilities related to encryption. Many modern web apps make heavy use of encryption, not just for keeping user accounts safe, but also to protect data both at rest and during transit. Generally, encryption techniques are developed and tested by cryptographers, but DAST is useful for testing the correct implementation of these encryption techniques. Cryptography is a highly specialized field and incorrect implementations can lead to security issues that are hard for non-specialists to identify, so this is very important for web app security.

Difficulty in Implementing DAST 

While DAST offers developers and testers many benefits, it’s nevertheless not commonly used as part of web app test suites. There are some reasons for this, primarily of which is the difficulty of implementing DAST. DAST requires testing an app through its front-end in real-world conditions. This means developers cannot make use of DAST during development. Testers can run tests in development environments, but as they tend to differ from production environments, there is an issue of accuracy and reliability regarding these test results. For many teams, this means testing on production or QA environments, which can be disruptive. Creating an environment that accurately mimics production in terms of server resources and capacity is difficult.

This is why services like Guide-Rails® allow you to create ephemeral environments for every push. An ephemeral environment is a short-lived environment that accurately mimics production and can be spun up on command. They’re intended to be used for exactly the kind of use cases as DAST – as a way to test against a realistic production environment without having to requisition the resources yourself or keep it running longer than necessary. Once you’ve finished testing, an ephemeral testing environment is destroyed to minimize unnecessary resource utilization and save on the associated expenses.

How It Is Transforming Modern Software Development

DAST provides another level of security to your web app security and testing suite. Traditional testing processes like SAST (static application security testing), unit testing, integration testing etc. all perform tests through code rather than the front-end. Oftentimes, these tests are run in isolation and under different environmental conditions than what will be used in production. For many years this has certainly been ‘good enough’, largely due to the technical difficulties of automating the provisioning of a production-level environment, running a test suite against it, and then winding it down once complete. However, thanks to services such as Guide Rails, this is now within the reach of any development team.

Final Thoughts 

Software testing is a never ending battle between testers and blackhats. Unfortunately for testers, there are many potential areas of vulnerability that testers have to cover, whereas blackhats only need to find a single exploit. DAST helps testers get ahead of blackhats by operating in the same environmental conditions and exploiting the same access points as blackhats. In the game of cat and mouse between testers and blackhats, every advantage is a welcome one.

If you’re interested in the benefits offered by DAST but don’t have the in-house knowledge to implement it yourself, or you simply want to know more about how DAST can help enhance your web app security testing, then get in touch with Guide Rails today. Proper DAST implementation is not easy, but the additional protection it provides is well worth the effort.