What is SAST?
Static Application Security Testing, or SAST, analyzes an application’s source code, bytecode or compiled code without executing it. It examines the internal structure of the application to identify security weaknesses before the software reaches production.
SAST tools can detect issues such as:
SQL injection risks
Cross-site scripting vulnerabilities
Insecure cryptographic implementations
Hardcoded credentials
Unsafe input handling
Weak authentication logic
Improper access controls
Vulnerable coding patterns
Because SAST examines the code itself, it can identify the location of a potential flaw and often indicate the file, function or line that requires attention. This makes it particularly useful for developers working during the coding and testing phases.
SAST can be integrated directly into an integrated development environment, a source code repository or a continuous integration pipeline. Developers can therefore receive feedback before a new feature is merged or deployed.
However, SAST does not observe the application while it is running. It may identify a potentially vulnerable function without showing whether that weakness can be exploited in the deployed environment.
What is DAST?
Dynamic Application Security Testing, or DAST, evaluates an application while it is running. Instead of reviewing the source code, DAST interacts with the application from the outside, sending requests and analyzing responses to identify exploitable vulnerabilities.
Dynamic Application Security Testing (DAST) involves analyzing an application's security while it is running in order to detect any vulnerabilities
DAST tools operate in a way that is closer to an external attacker or penetration tester. They can assess the security of web applications, APIs and other running services without requiring access to the underlying source code.
DAST is useful for detecting:
Authentication and session management flaws
Configuration weaknesses
Exposed endpoints
Runtime injection vulnerabilities
Server-side request forgery risks
Insecure headers
Access control issues
Unexpected application responses
Vulnerabilities caused by deployment settings
DAST is especially valuable in staging and pre-production environments, where the application can be tested in conditions that are close to its intended production configuration.
Its main limitation is that it may identify a vulnerability without explaining exactly where the problem exists in the source code. Developers may need additional investigation to identify the root cause and implement the appropriate fix.
SAST vs DAST: Key Differences
SAST and DAST differ mainly in what they analyze, when they operate and the type of feedback they provide.
Criteria | SAST | DAST |
|---|---|---|
Full name | Static Application Security Testing | Dynamic Application Security Testing |
Testing approach | Analyzes source code or compiled code | Tests a running application |
Perspective | Inside the application | Outside the application |
Typical phase | Development and code review | Testing, staging and pre-production |
Main strength | Identifies vulnerable code locations | Detects exploitable runtime behavior |
Source code required | Usually yes | No |
Feedback | Detailed and developer-oriented | Focused on application behavior |
Common limitations | May produce false positives or miss runtime issues | May not identify the source of the vulnerability |
SAST focuses on how an application is built. DAST focuses on how the application behaves when exposed to real requests. Neither approach provides complete coverage on its own.
When to Use SAST
SAST is most effective when security testing needs to begin early in the development process. Integrating it into the development workflow allows teams to detect vulnerabilities before they become difficult or expensive to correct.
+ During coding
Developers can use SAST tools to review new code as it is written. This helps identify insecure patterns before they are committed to a shared repository.
+ During code review
SAST can support pull request reviews by checking whether newly added code introduces security risks. The results can be used alongside manual review and software quality checks.
+ In continuous integration pipelines
SAST scans can be triggered automatically when code is committed or merged. Teams can define thresholds that prevent builds from progressing when critical vulnerabilities are detected.
+ For secure software development
SAST supports a shift-left security model, in which security controls are introduced earlier in the software development lifecycle. It can help organizations establish consistent coding practices across multiple teams and applications.
However, SAST results should be reviewed carefully. A static scan may flag code that is technically risky but not exploitable in the application’s actual context. Teams should combine automated findings with validation, prioritization and developer expertise.
When to Use DAST
DAST is most useful when the application is functional and available in a test environment. It evaluates the application as an external user or attacker would interact with it.
* Before production deployment
DAST can test a release candidate before it is deployed to production. This provides an additional control for identifying vulnerabilities that may not be visible through source code analysis alone.
* After configuration changes
Changes to servers, authentication providers, APIs, firewalls or deployment settings can create new risks. A dynamic scan can help verify that the running application remains properly protected.
* For third-party applications
DAST does not usually require access to source code. This makes it useful when an organization needs to test a vendor application, externally developed platform or legacy system.
* For web applications and APIs
DAST can simulate requests against public and private endpoints. It is particularly relevant for applications with complex integrations, user authentication and exposed APIs.
DAST results should also be interpreted in context. A scanner may identify a theoretical issue that requires authentication, a specific configuration or a particular sequence of actions before it can be exploited.
Why Organizations Need Both SAST and DAST
SAST and DAST are complementary security testing methods. SAST examines the application from the inside, while DAST tests its externally visible behavior. Using both approaches provides broader coverage across the software development lifecycle.
A typical workflow may look like this:
Developers run SAST scans while writing and reviewing code.
The development team fixes or prioritizes identified code-level vulnerabilities.
The application is deployed to a controlled testing environment.
DAST evaluates the running application and its exposed interfaces.
Security and development teams correlate findings and confirm remediation.
The application is approved for release when the remaining risks are understood and accepted.
This combination is a core component of a broader DevSecOps strategy. It allows security testing to become part of the delivery process rather than a separate activity performed only before an audit or major release.
Organizations building this type of workflow may benefit from cybersecurity consulting to define testing responsibilities, vulnerability priorities and remediation processes across development and security teams.
SAST and DAST in a DevSecOps Pipeline
Neither SAST nor DAST should operate as an isolated security tool. Their value depends on how effectively the results are integrated into the wider development and risk management process.
A mature DevSecOps pipeline should define:
Which vulnerabilities block a release
Who owns remediation
How false positives are reviewed
How findings are tracked over time
When applications must be rescanned
How security exceptions are documented
Which environments can be tested safely
SAST is generally positioned earlier in the pipeline, while DAST is introduced once the application can be executed. In some cases, organizations also use software composition analysis, infrastructure scanning, secrets detection and penetration testing to cover additional risk areas.
The objective is not to collect the highest possible number of findings. It is to identify meaningful weaknesses, prioritize them according to business impact and ensure that remediation is completed.
How to Choose Between SAST and DAST
The choice should depend on the application, the development stage and the risk the organization needs to manage.
Choose SAST when:
The source code is available
Developers need precise remediation guidance
The application is still being developed
Security checks must run during code integration
The organization wants to identify flaws early
Choose DAST when:
The application is running in a test environment
Source code is unavailable
Runtime behavior needs to be assessed
The organization wants to test exposed interfaces
Configuration and deployment risks are important
In most enterprise environments, the best approach is not to choose one over the other. SAST and DAST provide different forms of evidence, and their results can be combined to create a more complete view of application security.
A structured cybersecurity consulting approach can help determine which testing methods are appropriate for each application, based on its architecture, data sensitivity, exposure and release frequency.
Building a Sustainable Application Security Program
SAST and DAST are valuable controls, but they are only effective when they are supported by clear processes. Organizations should define secure coding standards, establish vulnerability ownership and create a consistent method for validating fixes.
Security testing should also evolve as applications change. New APIs, cloud services, authentication mechanisms and third-party dependencies can introduce risks that were not present in earlier versions.
The most effective programs combine automated testing with expert review, risk-based prioritization and continuous improvement. For teams that want to formalize this model across multiple applications, Mantu’s cybersecurity consulting services can support the definition of application security processes, testing strategies and remediation workflows.
SAST helps teams identify weaknesses in the code before deployment. DAST shows how those weaknesses, or other vulnerabilities, may affect the running application. Used together, they give development and security teams a stronger foundation for detecting and addressing application risks throughout the software lifecycle.
