Security threats and data breaches have become more common and may have huge financial and business implications for your organization. As such, you must be able to detect vulnerabilities in your applications fast.

There are several ways to find security vulnerabilities, and we’ll cover two application security testing methods in detail:

• What is SAST - Static Application Security Testing?
• What is DAST - Dynamic Application Security Testing?
• SAST vs. DAST: what’s the difference?

In this article, we are focusing on Dynamic Application Security Testing (DAST). Keep reading to know what DAST is, why it is important, and its pros and cons.

What is DAST?

Dynamic application security testing (DAST) is a black-box testing method that examines an application while it is running to find vulnerabilities that an attacker could exploit. These vulnerabilities include the OWASP Top 10 or the SANS/CWE 25.

Your team should be performing DAST on a running application in an environment similar to production. DAST tools scan the application from the outside in to identify run-time vulnerabilities. Those vulnerabilities are found later in the development lifecycle, making them harder for developers to fix. Remediation often gets pushed into the next cycle, and critical vulnerabilities often need to be fixed as an emergency release.

However, DAST is incredibly useful since it can detect security vulnerabilities that SAST cannot, like those that appear only during the program run-time. Examples include misconfiguration in servers or databases affecting security during run-time and authentication and encryption issues allowing unauthorized access.

Why is DAST important?

DAST tools automatically identify critical vulnerabilities within a running application. Although it’s applied later in the software development lifecycle, DAST should still be done before the application is released to the public. By doing so, DAST tools also decrease the potential impact of the identified issues. For example, if you didn’t find vulnerabilities before you deploy the application, it could lead to a severe data breach, resulting in financial loss and damage to your organization. 

DAST tools analyze your application at run-time, making it possible to find configuration and authentication problems or other runtime vulnerabilities that may impact your application’s functionality and security. It’s also a good method for preventing regressions and doesn’t depend on a specific programming language.

DAST tools are good at finding externally visible issues and vulnerabilities that external hackers would easily exploit to compromise your application. 

DAST can also help you in the process of being compliant with standards or getting certifications, like HIPAA or PCI DSS.

DAST pros & cons

DAST tools are great for analyzing running applications. However, they cannot identify vulnerabilities in the source code. As in every method, DAST has its pros and cons. Let’s take a close look at them.

Pros of DAST

• Low risk of reporting false positives: DAST identifies vulnerabilities on a running application by exploiting them. As such, it allows you to verify if a potential vulnerability is real and if it poses a threat to your application.
• Detection of runtime issues: DAST tools interact with a running application, enabling it to detect both compile-time and runtime issues.
• Works with every programming language: DAST is the only security method that isn’t programming language specific since it doesn’t look at source code. As such, if your application is implemented with a niche programming language, DAST may be your only choice.
• Uses regression testing: DAST makes it easy to check a previous vulnerability. If a vulnerability is reproduced, it can be added to the DAST test suit. As such, every subsequent release will include the same interactions that previously led to the issues.

Cons of DAST

• Doesn’t show problematic code locations: Since DAST doesn’t analyze code, it’s impossible to correlate the vulnerabilities and the exact line of code where they happened.
• Slower testing process: The requirements to execute and use a DAST tool can make the testing process slower, even when using automated testing methods.
• Fixing vulnerabilities is more expensive: Since DAST needs a deployed application, it can only be performed later in the development lifecycle, increasing the cost required to fix the identified vulnerabilities.
• Doesn’t have complete code coverage: DAST tools analyze a running application, meaning they might miss vulnerabilities in parts of the code that are not executed.
• Manual testing may be needed: Sometimes, it’s impossible to automate your application's execution and usage, so you’ll still have to test the application manually for every release.

Summary

DAST tools have great benefits but also some pitfalls. However, sometimes DAST is the only solution you can use, like when you’re using a niche programming language that is unavailable in other testing methods tools.

Still, whenever possible, it’s better to have a combined approach using SAST and DAST tools since it will allow you to find a broader range of vulnerabilities and weaknesses in your application. Plus, automating SAST and DAST scan with CI/CD allows you to accelerate development time without sacrificing your application’s security.

If you’re looking for a static analysis tool that allows you to check your code quality and keep track of your technical debt, try out Codacy today.