What Is Dynamic Application Security Testing (DAST)?

What Is Dynamic Application Security Testing (DAST)?

Dynamic Application Security Testing (DAST) is an application security testing methodology in which the application is tested at runtime to discover security vulnerabiltiies. DAST tools don’t have access to the application and API’s source code, so they detect vulnerabilities by performing actual attacks, similar to a real hacker. In a sense, DAST tools perform automated penetration testing of your web applications.

DAST solutions can detect and help protect against web application vulnerabilities, such as the OWASP Top 10. Common flaws include SQL injection, cross site scripting (XSS), external XML entities (XXE), and cross-site request forgery (CSRF). DAST can simulate these attacks and see if the application is vulnerable. While it is possible to scan source code to find vulnerabilities, the most effective method to protect an application is to determine if an external attacker can exploit them at runtime, when the full application is running with all its components.

This is part of an extensive series of guides about hacking.

In this article, you will learn:

• Why Is DAST Important?
• DAST Pros and Cons
• How Does DAST Work?
• What is the Role of DAST in Application Security (AppSec)?
• DAST Best Practices

Why Is DAST Important? 

Simply testing applications during development is insufficient for protecting them from potential breaches during their production stage. It is crucial to establish a diverse application security program to mitigate overall business risk. By utilizing DAST with other strategies, it is possible to detect potential attack vectors and prevent them from being exploited.

DAST solves these challenges and allows your organization to:

1. Provide accurate vulnerability reports based on the application’s running state
2. Support developer education by providing actionable fixes to security problems
3. Easily integrate security testing into the SDLC
4. Practice DevSecOps more effectively by taking feedback produced from DAST and integrating it into SecOps and DevOps tools
5. Better protect applications and code
6. Provide quality vulnerability assessment reports to expedite the remediation process

DAST is an essential component of a comprehensive security testing program, as it provides a real-world evaluation of an application’s security posture. It is typically performed as part of the software development lifecycle to ensure that security issues are identified and addressed before an application is released into production.

DAST Pros and Cons

Benefits of DAST

DAST offers several benefits, including:

• Identifying vulnerabilities: DAST tools can identify security vulnerabilities in web applications that could be exploited by attackers. This helps developers and security teams understand how an application may be exploited and take steps to remediate these vulnerabilities.
• Real-world testing: DAST tests an application in its operational state, allowing it to identify vulnerabilities that may not be caught by other types of security testing, such as static analysis or manual code review.
• Quick testing: DAST tools can quickly scan an application to identify vulnerabilities, allowing security teams to prioritize remediation efforts based on risk severity.
• Comprehensive testing: DAST can test the entire application, including its user interface, web services, and back-end components, providing a more comprehensive evaluation of an application’s security posture.
• Cost-effective: DAST is a cost-effective way to evaluate the security of web applications, as it does not require access to the application’s source code or specialized security expertise.
• Compliance: DAST can help ensure that web applications comply with industry standards and regulations, such as the Payment Card Industry Data Security Standard (PCI DSS) or the General Data Protection Regulation (GDPR).

DAST Limitations

While DAST is a powerful tool, traditional DAST has a few limitations, including:

• Limited coverage: Traditional DAST tools only test an application’s external behavior, such as its user interface and web services, and do not assess its internal workings. This limits their ability to identify certain types of vulnerabilities, such as those that occur in the back-end components of an application.
• False positives: Traditional DAST tools can generate false positives, which are warnings that a vulnerability exists when it does not. This can result in wasted time and effort, as well as lead to potential security gaps if real vulnerabilities are ignored due to too many false positives.
• Limited context: Traditional DAST tools operate without full knowledge of the application’s context, such as business logic or the intended user experience. This can result in a lack of accuracy in identifying vulnerabilities and their potential impact on the application.
• Inability to detect all types of vulnerabilities: Traditional DAST tools may not be able to detect all types of vulnerabilities, such as those that require a complex chain of actions to exploit.
• Requires significant expertise: Traditional DAST tools require specialized expertise to interpret the results and determine the severity of any identified vulnerabilities. This can be a significant challenge for smaller organizations or those with limited security resources.

Related content: Read our guide to dast vs sast.

How Does DAST Work?

DAST tools launch automated scans simulating malicious external attacks on the application. The goal is to identify unexpected outcomes. For example, a test can inject malicious data to uncover injection flaws. A DAST tool typically tests all HTML and HTTP access points. To find vulnerabilities, the test emulates random user behaviors and actions.

A new generation of DAST solutions is emerging, which leverages AI to address the challenges of traditional DAST:

• No need for manual tuning – next-generation DAST automatically creates test sets and dynamically identifies the structure of the underlying application.
• No false positives – leverages machine learning algorithms and fuzz testing to analyze findings like a human penetration tester, and determine if they are real vulnerabilities or not.
• Detects business logic vulnerabilities – accesses web applications like a real user and tries different control flows, until it discovers a user interface path that exposes a security weakness. 
• Detects zero day vulnerabilities – while traditional DAST can only detect known vulnerabilities from manually updated lists, next generation DAST leverages AI detection capabilities and real time data from other users of the platform to detect zero day attacks.
• Advanced reporting – provides reports and compliance audits on par with those created by a human tester. 

What is the Role of DAST in Application Security (AppSec)?

Application security testing (AST) tools automate the process of testing, analyzing, and reporting security vulnerabilities. AST tools are an integral part of the DevSecOps movement, which aims to shift security left and add security scans to each stage of the software development lifecycle (SDLC).

AST tools are typically categorized into four main types:

• Static application security testing (SAST) – provides white-box testing which analyzes the source code while its components are at rest.
• Dynamic application security testing (DAST) – provides black-box tests that models how applications are attacked from the outside.
• Interactive application security testing (IAST) – provides instrumentation of the application code. The goal is to detect and report issues during runtime.
• Software composition analysis (SCA) – scans the code and analyzes open source software components, looking for vulnerabilities and checking license compliance.

DAST vs. SAST

DAST solutions have unique advantages when protecting web applications:

•  A downside of SAST solutions is that they have to support the programming language and application framework in use by the application.
• In DAST, only issues that represent a real risk are reported. With SAST it can be challenging to determine if a finding represents a real risk or not.
• Modern DAST can be used as early as the build phase of the SDLC. You can simulate attacker behavior without lengthy pen-testing. SAST takes place earlier in the SDLC, but can only find issues in the code, not the full application.
• DAST detects risks that occur due to complex interplay of modern frameworks, microservices, APIs, etc. SAST solutions are limited to code scanning.
• In comparison to SAST, DAST is less likely to report false positives.

Unlike SAST tools, Dynamic analysis tools are language agnostic. They don’t need to have the same programming language or framework as the application you scan.

Dynamic application security testing solutions, like a real hacker, don’t have access to source code. Using them has more real-world benefits.

Learn more in our detailed guide to iast vs dast.

Integrating DAST into the SDLC

DAST has been around since the mid-90s, but until recently struggled to find its place in the SDLC.

DevOps brought the change. Today, dynamic analysis tools can be easily integrated with popular issue trackers such as JIRA, GitHub, ServiceNow, and Slack. Like any other type of automated AST solutions, DAST solutions can be integrated with CI platforms such as Jenkins, CircleCI, TravisCI, JFrog Pipelines or Azure DevOps.

Organizations want to implement application security testing into the SDLC because the sooner a security issue is detected, the cheaper it is to fix.

DAST Best Practices

Enable Effective Collaboration with DevOps

DAST tools can help not only discover and prioritize vulnerabilities, but also effectively hand them over to DevOps teams to ensure they are addressed correctly. To facilitate this, integrate the DAST tool with ticketing and bug tracking systems used by the DevOps team. Create tickets or issues with the precise information developers need to quickly fix vulnerabilities. This will help them prioritize security issues, and promote a DevSecOps mindset in your organization.

Adopt Defensive Coding Practices

DAST is more effective when the underlying application is built with security in mind. Defensive programming encourages developers to consider how attackers might exploit vulnerabilities and misconfigurations and then design preventive measures into the application while building it.

Developers do not need formal security training to write secure code. It only requires some basic precautions to ensure that the code they write does not contain commonly exploited misconfigurations and vulnerabilities.

Use DAST as Early in the SDLC as Possible

The earlier you integrate DAST into SDLC, the higher your returns will be. In general, early testing is ideal because it can detect vulnerabilities before they hit production, for remediation to be carried out earlier, making the fixes easier and cheaper. 

Integrate DAST with Your CI/CD Pipeline

You can run DAST at every stage of the CI/CD pipeline – early development, testing, staging, and production deployment. At every stage, DAST solutions will provide useful recommendations and reveal vulnerabilities. Identifying these vulnerabilities and fixing them immediately as they are introduced to the pipeline, can dramatically improve security and save time.

Bright’s Next-Gen DAST Solution

Unlike other DAST solutions, Bright was built from the ground up with developers in mind. It lets developers automatically test their applications and APIs for vulnerabilities with every build.

Bright tests every aspect of your apps. It enables you to scan any target, including web applications, internal applications, APIs (REST/SOAP/GraphQL), and serverside mobile applications. It seamlessly integrates with the tools and workflows you already use, automatically triggering scans on every commit, pull request or build with unit testing. Scans are blazing fast, enabling Bright to work in a high velocity development environment.

Instead of just crawling applications and guessing, Bright interacts intelligently with applications and APIs. Our AI-powered engine understands application architecture and generates sophisticated and targeted attacks. By first verifying and exploiting the findings, we make sure we don’t report any false positives. 

See Additional Guides on Key Hacking Topics

Together with our content partners, we have authored in-depth guides on several other topics that can also be useful as you explore the world of hacking.

Browser Security

Authored by Perception Point

• What is Browser Security?
• Cross Site Scripting (XSS) Attack: How It Works and How to Fix It
• Virtual Browsers: Concepts and Use Cases

System Hardening

Authored by Perception Point 

• System Hardening Guidelines: Critical Best Practices | Perception Point
• OS Hardening: 15 Best Practices
• Windows 10 Hardening: 19 Ways to Secure Your Workstations

Advanced Persistent Threat

Authored by Cynet

• What Is an Advanced Persistent Threat (APT)?
• How to Protect Your Business Against APT Malware
• APT Security: Attack Stages & 6 Ways to Secure Your Network

Subscribe to Bright newsletter!