What is DAST?
DAST stands for dynamic application security testing—a critical approach to web application security that zeroes in on real-life security risks by analyzing your running applications and APIs. It moves beyond the source code limitations of static application security testing (SAST) to identify application vulnerabilities in anything you are running, providing an outside-in, real-time view of your security posture across your real-world attack surface.
Why do organizations need DAST?
Finding and fixing application vulnerabilities is crucial for preventing security incidents, including serious data breaches. Unlike static testing tools that check the application source code, DAST tools work by probing entire running web applications and APIs. This black-box testing approach lets you detect not only OWASP Top 10 security vulnerabilities like SQL injection and cross-site scripting (XSS) but also misconfigurations and other runtime security issues undetectable with static testing. Accurate DAST tests are the automated counterpart of manual penetration testing, enabling a continuous security testing process for 
data-based AppSec.
How do DAST tools work?
Automated DAST tools test websites, applications, and APIs by safely performing a wide variety of simulated attacks and analyzing the reactions. There are three main stages of dynamic analysis, also called black-box testing:
- The DAST scanner uses a web crawler to map out a running application or site. It follows links and finds pages, forms, and app and APIÂ parameters.
- Once the entire application is mapped, DAST accesses each discovered input location such as form fields and API parameters, performing checks by sending data to the app and analyzing the responses.
- If the application reacts in a way that suggests or proves a vulnerability, for example by executing a test payload, the DAST tool records the precise location of the page and parameter along with the response, enabling faster prioritization and remediation of issues.
What are SAST and DAST?
Static application security testing (SAST), also called white-box testing, is performed in development by analyzing the source code to identify potential security flaws. In contrast, DAST tools crawl and scan an entire application from the outside to probe it for exploitable vulnerabilities, much like an attacker would. Unlike SAST tools, DAST scanners don’t require source code access and are technology-agnostic because they test application behavior from the outside. This allows DAST to test websites, web applications, and APIs regardless of the underlying tech stack or source code availability.
What are the advantages of DAST?
Dynamic application security testing is a critical component of any comprehensive cybersecurity program, working alongside testing methodologies like manual pentesting, SAST, software composition analysis (SCA), and interactive application security testing (IAST) to maximize testing coverage. At the same time, modern DAST brings some unique advantages to the table:
- DAST scans can run at many stages of the software development lifecycle, which you can’t do with most other security testing methods.
- Advanced DAST solutions can scan both apps and APIs, are independent of the frameworks and programming languages used, and can even automatically authenticate to test restricted pages.
- Compared to static analysis, high quality DAST scanners produce fewer false positives by working with actual application behaviors rather than suspicious code constructs, which helps development teams remediate real issues faster.
- You can run your DAST tools as often as you need and get results in a fraction of the time required by penetration testers.
When should you use DAST?
Modern DAST solutions like Invicti can be used at multiple stages of the development and operations pipeline, taking the load off DevOps and security teams to support an automated DevSecOps workflow:
- Dynamic analysis during application development: As part of shift-left efforts to run security testing earlier in the SDLC, running a DAST scan from the first builds in the CI/CD pipeline helps eliminate vulnerabilities before they can slip into later stages of the development process.
- DAST in staging and pre-release: Complete application functionality is usually only accessible once an app’s full architecture is put together, making pre-release dynamic testing imperative to catch issues such as misconfigurations and vulnerabilities in dependencies.
- Vulnerability scanning in production: For regular post-release scanning (also called shifting right), advanced DAST tools can be set up to periodically re-check production environments for vulnerabilities without hindering or disrupting normal operation.
