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What is Dynamic Application Security Testing (DAST)?  


Praise Iwuh

January 26, 2023


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The digital age has brought with it an ever-increasing need for secure applications. With the rise of malicious software, hackers, and other cyber threats, it is essential for companies to ensure their applications are protected. Application security testing is the process of scanning software applications for security weaknesses and vulnerabilities. It is done to detect, analyse, and report security threats and facilitate resistance. It is an integral part of software development. 
There are four basic Application Security Testing techniques: 
Dynamic application security testing (DAST) 
Static application security testing (SAST) 
Interactive application security testing (IAST) 
Software composition analysis(SCA) 
This article discusses DAST, its definition, types, importance, tools, pros and cons, and 


What is DAST? 

Dynamic Application Security is a testing technique designed to protect applications from malicious attacks by monitoring them in real-time. It uses a variety of techniques such as data leakage detection, behavioural analysis, and vulnerability scanning, to detect and respond to threats. This type of security also provides protection from zero-day exploits, which are new threats that have not yet been discovered.

It involves scanning for vulnerabilities while the 
app is running. It simulates an actual malicious attack and is done from “outside-in” without 
access to the source code and other internal details. 
DAST is a form of black box testing, which means it looks at the application's external 
interfaces and attempts to penetrate them just like an attacker would. 
Dynamic testing aims to ensure efficient application security by uncovering vulnerabilities in 
the security system, trying to exploit them and reporting the system’s response and 
susceptibility to these threats.  It is called “Dynamic'' because it functions while the 
application runs.

Types of DAST 

Although most DAST operations today are automated, it is relevant to note that there remain 
two approaches to Dynamic testing: 
Manual DAST: Manual testing, as the name implies, involves using human effort, 
knowledge, experience, and knowledge to uncover vulnerabilities. 
It is often done by a team of security professionals who test the application for bugs that 
usually escape automated scanners. It involves using human guile, which computers are still 
incapable of.
Automated DAST: This technique uses testing software to find and report vulnerabilities 
automatically. It involves the use of techniques such as crawling and fuzzing. 
Automated scanning detects a wide variety of vulnerabilities and saves time. 
You can get a better result by blending both methods, usually in the order of automated 
first to discover a multitude of errors and manually to identify the few which got past the 
automated scanning.

Why DAST is Important 

Dynamic Application Security is an important tool for organizations looking to protect their applications from the ever-growing threat of cyber attacks. It offers a proactive approach to security, allowing organizations to identify and respond to threats before they can cause any damage. Additionally, this type of security is much more cost-effective than traditional security methods, as it eliminates the need for manual patching and updating.
Today, millions of businesses use web applications to offer services and expand their reach 
globally. Web applications are programs stored on a remote server and accessed over the internet through a web browser interface.  
Our favourite apps, Netflix, Gmail, SpotifyWhatsapp, and Uber, are all web applications.  
They facilitate communication, sales, registration, information banking and customer service. 
Unfortunately, the growth of the new age technology and web application development 
backpacks the rise of cyber security attacks and data breaches. 
According to Sitelock's 2022 annual security report, there has been a 210% increase in cyber attacks since 2020. Also, the number of average attacks per site has risen to 172 daily, while the average cost of a general data breach was $4.217 million in 2021.
These statistics point out how necessary it is to engage in security testing. The more code 
we write, the more websites we build, the more there will be an increase in cyber threats 
and breaches.  
Shockingly, Cybersecurity Ventures reports that cybercrime has become more lucrative than 
the notorious international trade of illegal drugs. 
DAST can find issues in a dynamic environment, which are only visible when the app is run. 
Its outside-in approach also makes it possible to observe microservice interactions and 
identify their shortcomings. 
Though best practices recommend a blend of two or more different testing techniques, 
dynamic testing is important because it works by imitating the very threats you seek to 
defend against, thus finding and fixing loopholes before an attacker arrives to exploit them. 
Dynamic testing: 
  • Protects your applications and code  
  • Identifies vulnerabilities 
  • Provides vulnerability assessment reports to facilitate remediation

How DAST Works 

The Dynamic Application Security Testing tool is used when the application enters 
production or runtime in the initial stages of the software development lifecycle. 
DAST tools scan applications from the outside, hunting for vulnerabilities and trying to exploit 
them. A report is sent to identify the vulnerability whenever it detects a weakness. 
In everyday terms, DAST secures a house by testing its defences and trying to break in. It 
checks the doors and windows for any openings or weak locks through which unauthorised 
access can be gained.  
It also attempts to pick locks, batter down doors, smash windows, and makes a detailed 
report of how successful its attempts were and why.  
DAST works opposite to SAST, where the doors and windows are tested from inside the 
It tests all of your application’s endpoints, simulating different attacks while trying to find 
When Dynamic Testing finds a vulnerability, it sends an automated alert to the development 
team concerned for a solution. 
It is important to note that while DAST tools are commonly used for web applications, it also 
contains features designed to test non-web apps.  
To begin implementing DAST, here are a few steps you should follow: 
Interact with Users 
It helps to interview your users and document their interactions with your app. This process 
typically involves recording their activities on the app and their answers to strategic 
questions about their overall experience with the app. This is to get a clear picture of the 
app’s behaviour in user environments.  
Automate User Interactions  
Next is to script the user’s actions using an automation tool. This works best for Command 
Line Interface(CLI) and Application Programmer Interface(API) applications, but is also possible for Graphical User Interface(GUI). 
Integrate Test-Scripts into CI/CD Pipeline  
Once your priority use cases have been represented by automated interactions, you can 
then run test-scripts against your application while a DAST tool scans it.  When the first 
DAST run is complete, you can start addressing the uncovered security vulnerabilities. 
Integrate Regression Tests into Testing Suite  
If you find security vulnerabilities in your application’s day-to-day usage, you can add 
specific usage scripts to your test suite. This prevents the issues from reoccurring in the 
Some of the operations carried out during DAST are: 
  • Fault injection approach 
  • Automated testing 
  • Comprehensive web app security strategy 

Benefits of DAST 

 Technology independent 
Because DAST doesn’t look at source code, it is not language or platform specific. 
Not being limited to specific languages or technologies allows you to run one DAST 
tool on all your applications. 
Low false positives 
Based on OWASP’s Benchmark Project, DAST has a lower false-positive rate than 
other application security testing tools. Testers can zero in on real vulnerabilities 
while tuning out the noise. 
Identifies configuration issues 
DAST excels at finding security vulnerabilities that occur only when the application is 
operational. In addition, DAST attacks an application from the outside in, placing it in 
the perfect position to find configuration mistakes missed by other AST tools. 

Limitations of DAST 

Not highly scalable  
One of the main downsides to DAST is its heavy reliance on security experts to write 
effective tests, which makes it very difficult to scale. 
DAST does not have any visibility into an application’s code base. This means DAST 
can’t point developers to problematic code for remediation or provide comprehensive 
security coverage on its own. 
Slow scanning 
DAST is not known for its speed, and many users report scans taking too long. 
Forrester estimates that DAST scans can last 5-7 days. In addition, DAST 
scans typically find vulnerabilities later in the software development life cycle (SDLC), 
when they are more costly and time-consuming to fix. 


DAST (Dynamic Application Security Testing) is a type of testing that looks for security 
vulnerabilities by safely exploiting a running application from the outside. This testing type does not depend on the framework or programming language used. 
SAST (Static Application Security Testing) is a type of testing that includes code analyzers. It 
tests the source code for vulnerabilities by identifying its common patterns. These tools 
are language-specific and should be used only if you are developing your applications. 
DAST and SAST are rightly regarded as opposite application security testing methods. Here 
we look at their differences and interactions. 

Black-box vs White-box 

DAST is a black-box security testing approach that analyses the app from the outside while 
SAST is a white-box method that investigates the software from within. DAST is typically 
used in tandem with SAST to ensure thorough security evaluation.  
Source code examination 
DAST uses operational testing to detect runtime errors, while SAST searches source code 
when the app is static to assess potential security concerns and construction defects. SAST 
can detect coding faults down to the code line number, whereas DAST can detect defects in 
the data flow. 
Performance analysis 
DAST determines if a user has the authority to access resources and identify whether the 
user is a superuser on a rooted device. The static analysis does not allow for this.  
DAST works on a live web application, unlike SAST, and can trace vulnerable plugins, which 
in turn, elevates privilege.  
During static analysis (SAST), little information on memory usage and management is 
derived. However, dynamic testing detects even the portions of RAM that are susceptible to 

Can they be used together? 

Yes. SAST and DAST can and should be used together. When DAST tools are used, their 
outputs can inform and refine SAST rules, improving the early identification of vulnerabilities. 
This refinement process allows SAST to be the primary method of uncovering issues and 
DAST to be the verification check before a product is launched. 

Differences Between DAST and Penetration Testing(Pentesting) 

DAST is often mistaken for penetration testing. However, they are two different operations 
entirely. Their major similarity is that they both are black-box testing techniques, which find vulnerabilities from outside and attempt to exploit them. In this section, we will discuss their 
Penetration testing is an application security testing method that detects exploits by 
simulating a malicious attack. It targets servers, protocol interfaces, or other application 
systems to determine how susceptible to breaches. 
Penetration testing involves hiring professional security personnel who will think like a 
hacker and replicate their malicious actions. These security professionals are experts at 
breaching applications. They detect breaches and point out the specific weak points for the 
developers to seal. 
Some key differences between Dynamic application security testing and Penetration testing 
  • DAST works in a dynamic environment and is usually automated, while penetration testing uses dynamic and static methods, and the process is entirely manual. 
  • DAST tools can be run by security teams, developers or automatically without human intervention. On the other hand,  Penetration testing requires deep understanding and expertise. 
  • DAST tools are mostly automatic, while penetration tests are usually manual (automated penetration testing tools do exist, however). 
  • DAST tools are inexpensive and can typically run as often as needed (depending on the licensing model). Penetration tests conducted by ethical hackers are high-cost and limited to a single, well-scoped penetration test.
  • Dynamic testing can generate false positives, while Penetration testing does not result in false positives. However, modern DAST tools increasingly use artificial intelligence (AI) and fuzzing tools to provide reports with minimal to zero false positives. 
  • Dynamic testing saves cost because it can discover issues earlier in the development process, while Pentesting is usually conducted on production applications, resulting in a higher cost of remediating issues. 
  • DAST tools can be run at any time, enabling continuous testing and scanning of an application. Penetration testing is typically a quarterly or yearly operation.


Top 10 Dynamic Application Security tools 

Burp Suite is one of the world's most popular penetration DAST tools. It is often used for 
web application security to discover vulnerabilities and remediate them. 
ZAP is an open-source tool from OWASP (Open Web Application Security Project). This is a 
Dynamic Application Security Testing tool you can use to carry out penetration testing and 
can help discover vulnerabilities in your application. 
It is an application that currently helps an organisation measure and manage security risk 
and help remediate security vulnerabilities faster. 
Being an external attack surface management tool, Detectify is totally automated and 
powered by a world-class ethical hacking community. Security teams using Detectify can 
map out their entire attack surface to uncover anomalies and detect the latest business-
critical vulnerabilities in real-time, especially in third-party software, by applying hacker 
Invicti is an automated application security testing solution that allows enterprises to 
safeguard thousands of websites while drastically lowering the chance of an attack. 
StackHawk is a contemporary DAST tool designed for CI/CD automation. It helps developers 
to uncover and immediately fix security bugs rapidly. It provides all the necessary 
documentation and guides in fixing the issue and ways to prevent such issues from 
Beagle Security is a web application penetration testing tool that aids in the detection of 
vulnerabilities on your website before hackers exploit them. You can integrate 
automated penetration testing into your CI/CD pipeline with Beagle Security to uncover 
security concerns early in the development lifecycle and ship safer web applications with 
Beagle Security. 
AppScan is a dynamic application security testing solution for security professionals and 
pen-testers. AppScan scans the target app and tests for vulnerabilities using a robust 
scanning engine. 
Acunetix is an automated application security testing platform allowing small security 
teams to take on large-scale security concerns. Acunetix helps enterprises 
decrease risk across all sorts of online applications with fast scanning, comprehensive 
results, and intelligent automation. 
Fortify on Demand (FoD) is a Service offering full-featured Application Security. It provides a 
simple approach to getting started while also allowing for growth. Fortify on Demand also 
offers in-depth mobile app security testing, open-source analysis, vendor application 
security management, and static and dynamic security. Every test has false 
positives removed, and test results can be evaluated manually by application security 


Dynamic Application Security is an essential tool for organizations looking to protect their applications from the ever-growing threat of cyber attacks. It offers a proactive approach to security and can help protect against zero-day exploits, making it a cost-effective solution for any organization. With the right tools and strategies, organizations can ensure their applications are secure and protected from malicious threats.
DAST will detect threats or security vulnerabilities that 
are sometimes only visible after an app has been activated, thereby protecting the organisation’s 
product, investment, and reputation.. DAST has its benefits and limitations and will be most useful when applied in the right scenarios and in tandem with other methodologies, such as SAST. 

Praise Iwuh

Content Writer


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