Running applications change constantly, and new vulnerabilities can appear with every update, integration, or configuration change. When an organization wants to scan their applications after deployment, they rely on Dynamic Application Security Testing (DAST), a security practice that scans a live, running application from the outside, the same way an attacker would. This article explains what DAST is, how it works, what it finds, how it compares to SAST, IAST, and penetration testing, and how to set up a scanning program that keeps applications secure over time.
What Are Key Characteristics of DAST?
DAST has three defining traits:
- Testing the application during execution
- Analyzing the external behavior and responses
- Running on a scheduled or continuous basis
What Is Dynamic Application Security Testing (DAST)?
According to the OWASP DevSecOps Guideline, DAST is an automated black-box testing method. It
identifies vulnerabilities in a running application. Black-box testing requires no access to source
code. This feature makes DAST suitable for applications built with different technologies. Examples
include Java with Spring, Python with Django, and PHP with Laravel.
What Application Components Does DAST Target?
DAST targets 3 application components:
- Web applications, such as online banking portals and e-commerce stores
- APIs, such as REST and GraphQL interfaces
- Application endpoints, such as login pages and search forms
What Does DAST Analyze and Report?
DAST tests a live app from the outside and reports what is exposed. It has no visibility into the source code. The scanner evaluates only what the application exposes through HTTP and HTTPS. Each scan produces a vulnerability report. The report highlights security findings, severity ratings, and affected URLs.
How Does a DAST Scan Work?
A DAST scan sends simulated attack requests to a running application. It then analyzes the responses to identify vulnerabilities.
What are the Steps of the Scanning Process?
The process has 5 steps:
- Scan: The scanner crawls the application and maps pages, forms, and API endpoints.
- Identify: The scanner sends test payloads, such as malicious SQL strings and script tags. It then records any abnormal responses.
- Prioritize: The scanner rates each finding by severity and exploitability. The ratings include critical, high, medium, and low.
- Remediate: Developers fix the confirmed vulnerabilities.
- Retest: The scanner runs again to verify each fix.
What Scan Modes Does DAST Support?
DAST supports two scan modes:
- Unauthenticated scans
They test pages open to any visitor, such as home pages and contact forms.
- Authenticated scans
They use test credentials to reach pages behind a login, such as user dashboards or admin panels.
What Vulnerabilities Can DAST Find?
DAST finds six vulnerability types that appear only when an application is running:
- SQL Injection
Attackers inject malicious SQL code into inputs, like login forms and search boxes.
- Cross-Site Scripting (XSS)
Attackers inject malicious scripts into pages viewed by other users.
- Broken Authentication
Weak login and session controls let attackers take over accounts.
- Access Control Flaws
Users access data or functions they are not allowed to use, such as other people’s account records or admin pages.
- Security Misconfiguration
Servers and applications expose default settings, error messages, and publicly accessible directories.
- Input Validation Issues
Applications accept unexpected data, such as oversized files and special characters.
What are the Limitations of DAST?
DAST has 3 limitations:
- Produces false positives, such as flagged issues that are not exploitable. Manual review is required before remediation
- Misses untested areas, such as hidden pages and unreached features
- Lacks source code visibility, so developers must locate the faulty code line themselves
How Is DAST Different from SAST, IAST, and Penetration Testing?
DAST differs from the other methods in what it tests and when it tests.
| S.No | Practice | Testing Focus | Application Status | Typical Stage |
|---|---|---|---|---|
| 1 | DAST | External behavior and responses | Running | Testing, staging, production |
| 2 | SAST | Source code | Not Running | Development |
| 3 | IAST | Runtime behavior through instrumentation | Running | Testing, QA |
| 4 | Penetration Testing | Application, APIs, and infrastructure | Running | Pre-release, annual audits |
Are you unsure which one to pick? If the application is running and requires scheduled scanning, the answer is DAST!
DAST vs SAST
DAST tests a running application. SAST analyzes source code without executing it. SAST locates the exact faulty line of code. However, DAST detects issues that appear at runtime. These issues include server misconfigurations and session flaws.
DAST vs IAST and Penetration Testing
IAST places sensors inside the running application and monitors code behavior during testing. Penetration testing uses human testers who chain multiple weaknesses into real attack paths. DAST automates external testing, making recurring scans faster. This testing may also be cheaper than manual penetration tests.
How Often Should an Organization Scan Its Applications?
Organizations usually have four approaches for running DAST scans:
- Scheduled Intervals
Weekly scans suit high-risk applications, such as banking portals and payment checkouts. Monthly or quarterly scans suit lower-risk applications, such as internal HR portals and company wikis.
- Major Releases
Each release adds new code, pages, and endpoints, so a scan follows every deployment.
- Significant Changes
Server migrations, payment gateway integrations, and framework upgrades alter the attack surface.
- CI/CD Pipelines
Automated scans run on every build in staging. They use tools such as Jenkins and GitHub Actions and give developers fast feedback.
Periodic scanning finds vulnerabilities introduced between scans. Continuous scanning shortens the gap between introduction and detection. For organizations that handle payment card data, the PCI Security Standards Council requires external vulnerability scans at least once every 3 months and after any significant change. So, scanning once is not enough, because every new release can add new risks!
How Should an Organization Set Up DAST Scanning?
DAST setup requires 6 configuration steps:
Define Scan Scope
List the target URLs, APIs, and subdomains (e.g., app.example.com). Exclude third-party services the organization does not own. Such services include payment gateways and analytics platforms.
Choose the Environment
Staging environments allow aggressive testing without risking live data. Production scans use safer scan profiles. This approach is important because test payloads can create records or trigger alerts.
Configure Authentication
Create test accounts for each user role, such as a standard user and an administrator. These dedicated accounts allow the scanner to access pages behind a login.
Protect Application Availability
Schedule scans during low-traffic hours and limit request rates to prevent slowdowns.
Set Up Reporting
Route findings with severity ratings and affected URLs to ticketing tools. Jira and GitHub Issues are examples of such tools.
Plan Retesting
- Rescan after each fix to confirm that you have resolved the vulnerability.
- DAST tools that support these settings include OWASP ZAP, Burp Suite, Invicti, and Acunetix.
- Start Small: Scan one application, fix the findings, then expand to the rest!
What Other Questions Do People Ask About Scanning Running Applications?
Here are 5 common questions about DAST and application scanning:
Question 1: Is DAST the Same as Vulnerability Scanning?
No. DAST is a type of vulnerability scanning that targets running applications. Network vulnerability scanning targets hosts, open ports, and services instead.
Question 2: Can DAST Scan an Application in Production?
Yes, DAST can scan production applications. It can use non-destructive scan profiles, limited request rates, and dedicated test accounts.
Question 3: Does DAST Need Access to Source Code?
DAST does not need access to source code. The scanner tests the application only through HTTP and HTTPS requests.
Question 4: Can DAST Run Automatically?
DAST runs automatically. It uses built-in schedulers and CI/CD integrations, like Jenkins and GitHub Actions.
Question 5: Is DAST Enough on Its Own?
No. DAST covers runtime vulnerabilities, while SAST covers code-level flaws. Combining both methods gives broader coverage.
Where Can Your Organization Get Application Security Scanning Services?
Apprise Cyber Pvt Ltd is a Pakistan-based cybersecurity company. It provides application security scanning and testing services. Apprise Cyber offers services to organizations that require vulnerability detection in running applications. It combines automated scanning with manual testing by Team Stealth-X, its offensive security team.
What are the Core Services of Apprise Cyber Pvt Ltd?
Apprise Cyber offers 4 core services for application security:
It identifies vulnerabilities and validates which ones may be exploitable.
It simulates real attacks on a vulnerable application. This approach shows what systems or data an attacker could access.
It reviews cloud configurations, such as AWS environments, for security misconfigurations.
Does your organization need application security scanning? Contact Apprise Cyber to schedule a vulnerability assessment!
