What is Dynamic Application Security Testing?

What is Dynamic Application Security Testing

Dynamic Application Security Testing (DAST) tools allow web applications to be monitored while running, regardless of programming language used, to identify vulnerabilities within front-end web technologies or server misconfiguration.

Cybercriminals continue to increase in sophistication, so security teams must employ various testing methodologies. DAST is an increasingly popular solution for providing visibility into vulnerabilities within software applications and helping achieve compliance.

What Is DAST?

DAST is an automated software application security testing solution, used to scan applications while they’re running and without access to their source code. It detects vulnerabilities by simulating malicious external attacks against an application in order to find outcomes not expected or part of its design.

DAST technology can identify many issues that expose your application to security threats, such as cross-site scripting (XSS) or SQL injection, as well as test its endpoints and APIs used by it, including any hidden configuration errors such as open ports and unsecure credentials that aren’t exposed in its source code.

DAST is language and platform agnostic due to not relying on source code; therefore it can scan all applications regardless of the language or platform they were written in. Furthermore, its lack of limitations means less likely false positive results compared with traditional SAST tools that scan source code without differentiating between code modules.

DAST provides another benefit of automation by being integrated seamlessly into your development workflow and making use of its automated processes simple. This makes DAST ideal for use within continuous integration/continuous delivery pipelines so as to detect vulnerabilities before they reach production, helping ensure your applications meet industry standards such as NERC CIP, PCI and HIPAA compliance.

When selecting a DAST solution, your goal should be to find one which can detect all the vulnerabilities your organization faces – both global such as OWASP Top 10 and SANS/CWE 25 vulnerabilities as well as industry-specific ones. Furthermore, look for solutions which support multiple interfaces (HTTP and HTML), and modern frameworks like React/Angular.

At the core of it all lies your decision for a DAST solution is making retesting vulnerabilities after they’ve been addressed easier – this way you can ensure that the fixes have taken hold and don’t resurface in future versions of applications. A good DAST should include internal systems for marking resolved or closed vulnerabilities as well as integrations with issue trackers so automated retests after vulnerabilities have been addressed can take place quickly and easily.

How Does DAST Work?

DAST tools detect web application vulnerabilities by simulating malicious attacks while the software is running, without accessing its source code or needing source access for these tests. DAST scanners do not need access to source code in order to simulate attack vectors which static analysis tools (SAST) cannot, such as cross-site scripting, command/SQL injections, path traversal attacks and insecure server configurations; and DAST can even identify security flaws which a human attacker might miss such as missing authentication/authorization controls or being unable to install an SSL certificate on web servers – providing insight into security vulnerabilities in web applications without source access required from within.

DAST and SAST work hand-in-hand to provide a more complete picture of an application’s security posture. By working in tandem, these methods help minimize vulnerabilities discovered and speed their remediation; helping developers and QA teams discover most security issues before they make it into production.

DAST is an ideal black-box assessment tool, as it does not rely on source code to assess software it is testing, making it ideal for running applications in production or test environments. Furthermore, its black-box approach enables it to identify security risks that would otherwise remain undetected such as those related to dynamically generated content or third-party libraries that SAST would struggle to uncover.

Effective DAST scanners feature low false positive rates to prevent developers from spending too much time addressing risks that don’t pose a real threat. Furthermore, these tools tend to be language agnostic so as to evaluate applications written for any programming language and environment.

DAST can either be completed manually or automatically. Manual scans tend to be ad hoc and difficult to integrate into an SDLC process, while automated DAST runs on an automated continuous integration/deployment platform like Jenkins so results can be added directly into developers’ bug trackers.

As DAST tests an application under running conditions, it should be implemented early in the SDLC to detect vulnerabilities before they reach production. Some organizations choose to deploy it after coding when its results can help identify weaknesses in existing codebase and refine SAST rules for improved detection of vulnerabilities in future releases.

How Does DAST Help?

Application vulnerabilities are one of the primary sources of cyberattacks, making DAST an essential tool in detecting them. DAST allows developers and security teams to improve overall application security by quickly detecting vulnerabilities that SAST or other automated testing tools missed, making remediation simpler for flaws that might otherwise have been missed altogether.

Dynamic DAST scanning involves sending data against an application using a scanner, fuzzer or crawler in order to identify potential issues. As opposed to SAST which works based on models of an application, DAST tests for real-world scenarios that could be encountered by malicious actors – for instance cross-site scripting attacks and SQL injection flaws.

Since DAST doesn’t rely on source code, it is language and technology agnostic and can be utilized across a variety of programming languages and technologies. A DAST scanner can even be run against Single Page Applications built using React or Angular frameworks as well as GraphQL APIs – this ensures all your code is being tested thoroughly while also detecting any vulnerabilities which could impact users.

DAST can be used by itself, or combined with SAST in a continuous integration and continuous delivery (CI/CD) pipeline to provide full application coverage. Together these technologies allow you to uncover any vulnerabilities present in your software before they’re exploited by attackers and rectify them before any attack occurs.

Like any automated testing method, DAST may produce false positives that require experienced developers to spend time determining if an apparent vulnerability exists or not, slowing the speed and effectiveness of testing processes.

DAST can also be slow, with Forrester noting that performing a DAST scan could take between 5-7 days to complete, potentially delaying detection until security issues become more costly and time consuming to address.

DAST can be difficult to scale due to its dependence on security experts for effective testing, making it more challenging than other SAST solutions which don’t necessitate security expertise to cover all vulnerabilities in an application.

What Is the Best DAST Tool?

The ideal DAST tool will offer comprehensive scanning, intuitive user interfaces and detailed reporting capabilities. This means being able to scan the full attack surface including servers, environments (both cloud and on-premises), API endpoints and infrastructure – as well as applications via both ad hoc and continuous testing modes based on your needs – with DAST capable of detecting vulnerabilities via server responses that indicate security weaknesses.

Rapid7’s InsightAppSec, Checkmarx Security Composition Analysis and StackHawk are among the premier DAST tools. Scalable and easily integrated into DevOps pipelines for automatic testing when code changes occur, they have low false positive rates while providing clear visibility of application vulnerabilities – these DAST tools are popular among security teams, software engineering teams and penetration testers alike.

Another approach is using a dynamic scanner, which can quickly identify vulnerabilities in running code by analyzing inputs and outputs without access to source code. This type of DAST testing, often called open source analysis or black box testing, mimics an attacker’s perspective without knowledge about inner functions of application; and may be combined with SAST tools in order to uncover gaps that the SAST tools cannot find.

Both DAST and SAST are essential tools for increasing application security by detecting weaknesses at runtime rather than static analysis, such as static analysis. They should be deployed early in the SDLC lifecycle so they can spot vulnerabilities before they make it to production; their deployment helps shift responsibility for security to developers themselves so that any flaws can be fixed before any harm comes their way.

With more organizations adopting DevOps to accelerate deployment, demand for DAST and SAST tools will only continue to increase. By taking an informed and strategic approach when choosing their DAST/SAST tool of choice, your application development team can craft safe, reliable apps which earn the trust of both customers and partners alike.

Mark Funk
Mark Funk is an experienced information security specialist who works with enterprises to mature and improve their enterprise security programs. Previously, he worked as a security news reporter.