# SAST, DAST, SCA and Pentest: What Are the Differences and When to Use Each?

**URL:** https://securesys.com.tr/en/learning/source-code-analysis/sast-dast-sca-pentest-differences

![SAST, DAST, SCA and Pentest: What Are the Differences and When to Use Each?](/images/bilgi-merkezi/covers/cover-kod-08.webp)

When modern application security is discussed, some of the terms encountered most often are:

#### SAST

#### DAST

#### SCA

#### Pentest

All of these methods serve application security.

But they do not do the same thing.

They look at different points.

They see different vulnerabilities.

They are run at different times.

And most importantly, they are complementary, not alternatives to one another.

An organisation cannot fully secure its applications using SAST alone.

Nor can it assure the entire software development life cycle by doing only penetration testing.

Without SCA, the risk in open source components can stay invisible.

Without DAST, the running application's real behaviour may not be assessed adequately.

The real question is therefore not:

**"Which one is better?"**

The right question is:

**"Which security method sees which risk, and how should we use them together?"**

In this chapter we will compare the SAST, DAST, SCA and pentest approaches from technical, operational and enterprise perspectives.

Our aim is not only to explain the concepts but to clarify which security method should be used in which situation.

### \1. Why Does Application Security Not Consist of a Single Test?

An application's security is multi-layered.

The application's:

- source code,
- open source components,
- runtime behaviour,
- API surface,
- authentication structure,
- authorisation mechanism,
- business logic,
- deployment environment,
- CI/CD process

together determine its security.

No single security tool can analyse all these areas at the same depth.

SAST can see source code very well, for example.

But it may not assess the HTTP security headers in the production environment.

DAST can test the running application.

But it cannot see the hard-coded API key inside the source code.

SCA analyses open source dependency risks.

But it cannot detect the application's business logic flaws.

A pentest simulates real attacker behaviour.

But it cannot systematically scan every one of millions of lines of code.

The basic principle of Application Security is therefore:

**Layered security instead of a single control.**

### \2. What Is SAST?

SAST is the Static Application Security Testing approach.

It analyses source code or related software components without running the application.

SAST's basic question is:

**"Is there a security-risky structure inside the code?"**

For example:

- does user input reach an SQL query insecurely?
- does user-controlled data go to a command execution function?
- is sensitive information kept inside the code?
- is an insecure cryptographic function being used?
- is input validation missing?

SAST is strong particularly at the development stage.

Because a security problem can be detected before it reaches the production environment.

### \3. Where SAST Is Strongest

SAST is strong particularly on security problems visible at code level.

For example:

- SQL Injection
- Command Injection
- some types of XSS
- Path Traversal
- insecure deserialization patterns
- hard-coded credentials
- insecure crypto usage
- dangerous function calls
- input validation problems

SAST can also show which file and line the finding is on inside the source code.

That is an important advantage for developers.

The finding can be tied directly to the point where remediation will happen.

### \4. SAST's Limits

SAST's most important limit is that it does not see the application's real runtime behaviour.

For example:

- runtime configuration,
- proxy behaviour,
- WAF effect,
- the real behaviour of session management,
- CORS implementation,
- business logic attacks

may not be fully understood by SAST.

Complex authorisation problems and attack chains can also require human analysis.

SAST therefore provides:

**"code security visibility"**

but does not on its own represent an application's whole security.

### \5. What Is DAST?

DAST is the Dynamic Application Security Testing approach.

It tests the running application from outside.

It does not have to have access to the source code.

DAST's basic question is:

**"Is the running application open to attack from outside?"**

The DAST system analyses behaviour by sending HTTP or similar requests to the application.

Test inputs can be sent to fields such as:

- query parameters,
- form inputs,
- API bodies,
- URLs,
- headers.

The responses the application gives are analysed.

### \6. Why Is DAST Close to the Black Box Approach?

Because DAST usually sees the application from outside, it is close to black box testing.

That is, the system can test without knowing the application's internal code structure.

An attacker also usually approaches the application from outside.

DAST therefore provides a perspective closer to the real attack surface.

But it should not be said that it fully simulates attacker behaviour.

Because automated DAST systems also work with particular scanning logic.

They are not as creative as a human pentester.

### \7. Which Vulnerabilities Can DAST Find?

DAST can try to detect many security problems in the running application.

For example:

- SQL Injection
- XSS
- some authentication problems
- server misconfiguration
- missing security headers
- exposed endpoints
- some SSRF scenarios
- exposed sensitive data

DAST's important advantage is that the finding is observed in the genuinely running application.

In some cases exploitability can therefore be understood more clearly.

### \8. Where Is DAST Strongest?

One of the areas where DAST is strongest is runtime behaviour.

A system that looks secure in the source code may be weak because of production configuration, for example.

Because DAST assesses the running application, it can see problems of this kind.

Runtime characteristics such as:

- response headers,
- cookie attributes,
- HTTP methods,
- error handling,
- public endpoint behaviour

can also be analysed better.

### \9. DAST's Limits

DAST sees the outside of the application.

It does not see the internal source code.

It may therefore not detect problems such as:

- hard-coded credentials,
- an unused but risky function,
- a weak algorithm inside the code,
- internal security logic.

Endpoints the scanner cannot reach or the crawler cannot discover can also be missed.

If authentication flows are complex, DAST's coverage can be limited.

### \10. The Basic Difference Between SAST and DAST

In the simplest terms:

**SAST looks from the inside out.**

**DAST looks from the outside in.**

SAST examines the source code.

DAST sends requests to the running application.

SAST is closer to the developer's perspective.

DAST is closer to the attacker's perspective.

When used together they therefore provide far stronger visibility.

### \11. Can SAST See a Vulnerability DAST Cannot?

Yes.

A function open to SQL Injection may be present in the source code, for example.

SAST can detect that function.

But the relevant endpoint may not be reachable in the production environment.

DAST may therefore not see the vulnerability.

In another example, a hard-coded credential may be present inside the code.

DAST may never see it.

That is SAST's advantage.

### \12. Can DAST See a Vulnerability SAST Cannot?

Yes.

A missing security header may stem from the reverse proxy configuration in the production environment, for example.

SAST may not see that information inside the code.

Similarly, CORS behaviour or a session cookie attribute can be created at runtime level.

DAST can detect that better.

The two methods therefore see different security layers.

### \13. What Is SCA?

SCA is the Software Composition Analysis approach.

SCA's basic question is:

**"Which third-party components does our application use, and do they contain known vulnerabilities?"**

Because a large number of open source packages are used in modern applications, this question has become critical.

SCA can analyse:

- dependencies,
- package versions,
- known CVEs,
- licence information.

### \14. Why Is SCA Different from SAST?

SAST mostly analyses first-party code.

That is, code written by the organisation's developers.

SCA focuses on third-party code.

That is, libraries the organisation did not write but uses.

For example:

SAST can find the injection risk in an SQL query you wrote.

SCA can find a known CVE in the JSON parser library you use.

These two risks are entirely different.

### \15. Why Is SCA Becoming Mandatory in Modern Software?

Because software development can no longer be considered independently of the open source ecosystem.

An application can contain hundreds of dependencies.

With transitive dependencies the number can be far higher.

The organisation's developer may have added only 10 different packages.

But hundreds of packages can be present in the real application.

The dependency inventory therefore cannot be managed manually.

SCA automates that visibility.

### \16. Which Risks Does SCA See?

SCA is strong particularly in these areas:

- known CVEs,
- vulnerable package versions,
- transitive dependencies,
- EOL dependencies,
- licence risk,
- dependency inventory.

More advanced systems can also provide information such as:

- reachability,
- exploit intelligence,
- remediation guidance.

### \17. SCA's Limits

SCA sees only dependency security.

It does not assess the injection problem in the application's own code.

It does not find business logic flaws.

It does not analyse authentication design.

SCA therefore focuses on the:

**"dependency security"**

area.

Using SCA together with SAST is therefore important.

### \18. What Is a Pentest?

A pentest — penetration testing — is the assessment of a system's security as closely as possible to a real attacker's perspective.

During a pentest the security specialist analyses the application's attack surface.

They can use automated tools.

But the decisions and attack logic are driven by the human specialist.

The aim is not merely to scan for known vulnerabilities.

It is to understand how the application could be abused.

### \19. Why Is a Pentest Not an Automated Scan?

Automated vulnerability scanners can be used during a pentest.

But a pentest does not consist only of that.

The security specialist:

- explores the application,
- analyses the differences between roles,
- compares endpoints,
- performs parameter manipulation,
- builds attack chains,
- tries to understand the business logic.

A pentest therefore requires human creativity.

### \20. Where Is a Pentest Strong?

A pentest is strong particularly in these areas:

- Broken Access Control
- IDOR / BOLA
- Business Logic
- Authentication bypass
- Authorization bypass
- Session problems
- Race Condition
- API abuse
- Attack Chaining
- complex runtime vulnerabilities

These are the areas automated tools struggle with most.

### \21. A Pentest's Limits

A pentest is very valuable but is performed within a defined period of time.

In a five-day test, for example, the security specialist cannot examine the whole application at unlimited depth.

The code can also keep changing.

A new vulnerability can be added a week after the pentest finishes.

A pentest therefore does not take the place of continuous AppSec controls.

A pentest should be thought of as:

**a periodic or post-critical-change deep verification layer.**

### \22. The Difference Between SAST and a Pentest

SAST scans source code systematically.

A pentest assesses the running application's attack surface.

SAST can provide very broad code coverage.

A pentest provides deeper attacker logic.

SAST might say:

**"There is no authorisation check on this endpoint."**

A pentester can use that gap to show the real impact:

**"A standard user can perform an admin operation."**

### \23. Are DAST and a Pentest the Same Thing?

No.

These two methods are confused particularly often.

Both can test the running application.

But DAST is an automated security test.

A pentest is an attack simulation carried out by a human specialist.

DAST can scan hundreds of endpoints quickly.

A pentester can understand the relationship between different endpoints.

It can therefore be summarised as:

**DAST = Automated dynamic testing**

**Pentest = Human-driven attack testing**

### \24. Can DAST Replace a Pentest?

No.

DAST can reduce the pentester's workload.

It can detect known security problems quickly.

But it is limited in areas such as business logic and attack chaining.

The strongest model is to use:

#### DAST + Manual Pentest

together.

DAST provides broad automated scanning.

The pentester goes deep in the critical areas.

### \25. Can SAST Replace a Pentest?

No.

SAST provides very deep visibility into source code.

But it does not see the running application's real behaviour.

The authentication check may look correct in the code, for example.

But an endpoint may have been left public because of the reverse proxy or deployment configuration.

A pentest can see that problem.

Similarly, a human can understand business logic flaws better.

### \26. Can SCA Replace a Pentest?

No.

SCA analyses known dependency risks.

A pentest assesses the application's real attack surface.

But it is not efficient for a pentester to examine hundreds of dependencies manually for CVEs either.

SCA automation is therefore necessary.

### \27. Which Test Should Be Done When?

In a practical software life cycle, tests can be placed at different stages.

#### While Code Is Being Written

Secure Coding

IDE Security

#### Commit / Pull Request

Secret Scanning

SAST

SCA

#### Build

SAST

SCA

Container Scanning

#### Test Environment

DAST

API Security Testing

#### Before Release

Pentest

Manual Security Review

#### Production

Continuous Monitoring

Periodic Pentest

This structure spreads security across the whole life cycle.

### \28. Which Method Is Most Suitable for Shift Left?

SAST and SCA are quite suitable from a Shift Left Security perspective.

Because a security check can be made at an early stage without needing the application to run.

When the developer creates a pull request:

- SAST,
- SCA,
- Secret Scanning

can be run automatically.

A security problem is then detected before it comes near production.

### \29. What Is Shift Right?

While Shift Left moves security to an early stage, Shift Right focuses on production and runtime security.

For example:

- runtime security,
- WAF,
- application monitoring,
- SIEM,
- RASP,
- production pentesting

are closer to the Shift Right perspective.

A strong security programme does not only Shift Left.

#### Shift Left + Shift Right

are applied together.

### \30. Which Method Is More Effective for API Security?

No single method is sufficient for API security.

SAST:

can see the problems in the API's source code.

DAST:

can test API endpoints automatically.

SCA:

analyses the libraries the API service uses.

Pentest:

tests BOLA, BFLA and business logic attacks more deeply.

A layered approach is therefore needed for API security too.

### \31. Which Method Is Stronger for Business Logic?

For business logic security problems, manual pentesting and manual code review are stronger.

Because finding these flaws requires understanding the application's business model.

Questions such as:

**"Why should this coupon only be used once?"**

or:

**"Why should this user not be able to perform this operation?"**

are contextual.

An automated tool may not know that business rule.

### \32. Which Is Better for SQL Injection?

SQL Injection can be detected at different layers.

SAST can see the risky data flow inside the source code.

DAST can test the flaw by sending a payload to the running application.

A pentester can manually try more complex bypass techniques.

There is therefore no single "best" method.

The strongest model is the combination:

**SAST + DAST + Pentest**

### \33. Which Is Better for Hard-Coded Secrets?

This problem is at code and repository level rather than runtime.

The most suitable method is:

#### Secret Scanning

and secondly SAST.

DAST or a pentest may not see a secret left inside the code that is not visible at runtime.

This example shows clearly that every security problem requires a different tool.

### \34. Which Is Used for a Vulnerable Open Source Library?

The right answer is:

#### SCA

SAST can in some cases analyse the code inside a dependency, but third-party component inventory and CVE management are SCA's area.

A pentest can exploit a known dependency flaw.

But SCA manages which of hundreds of libraries are risky far better systematically.

### \35. Which Is Stronger for Authentication Problems?

Because authentication is multi-layered, different methods can be used together.

SAST:

can see errors in the authentication code.

DAST:

can test login and session behaviour automatically.

Pentest:

can assess MFA bypass, password reset abuse and complex session attacks.

Manual analysis is generally critically important.

### \36. Which Is Stronger for Authorization Problems?

Authorisation requires business context in particular.

Therefore:

#### Manual Pentest + Manual Code Review

is one of the strongest combinations.

SAST can find some missing security annotation or authorisation check problems.

DAST can detect some object access problems.

But human analysis is needed to understand the whole role matrix.

### \37. Is SCA Enough Against a Zero-Day?

If SCA relies on known vulnerability databases, it may not see a zero-day that has not been disclosed yet.

The same problem can apply to other automated technologies.

Security should therefore not rest on known CVEs alone.

Methods such as pentesting,

manual code review,

behaviour monitoring

can surface unknown risks.

### \38. Which Method Produces More False Positives?

This varies according to the tool and configuration.

But automated technologies can generally produce false positives.

Misinterpreting the data flow in SAST,

misassessing response behaviour in DAST,

a package CVE not being reachable from the application's perspective in SCA

are examples.

Triage is therefore important in all automation.

### \39. False Negative Risk

No tool can find every vulnerability.

SAST can miss particular business logic.

DAST cannot test an endpoint it could not discover.

SCA cannot know a CVE that is not yet known.

A pentester can miss some areas because of time constraints.

The basic principle in security is therefore:

#### Do not rely on a single control point

### \40. What Does Defence in Depth Mean in Application Security?

Defence in Depth is the layered security approach that aims for another control to reduce the risk when one security control fails.

An example in Application Security:

SAST tries to find the problem while the code is being written.

DAST tries to find it in the test environment.

A pentest performs attack simulation before release.

A WAF tries to block the exploit attempt in production.

The SOC monitors suspicious behaviour.

Even if one layer misses the problem, the next layer can catch it.

### \41. What Should the Security Testing Pyramid Look Like?

Application security tests can be thought of as a pyramid.

Frequent, automated tests are at the bottom.

For example:

**SAST + SCA + Secret Scanning**

can run on every commit or build.

In the middle layer:

#### DAST + API Security

can be placed.

And in the top layer, less frequently but more deeply:

#### Manual Code Review + Pentest

can be applied.

This structure provides both scale and depth.

### \42. Why Can a Pentest Not Be Done on Every Commit?

A pentest requires human expertise.

A manual pentest for every commit is not possible economically or operationally.

Automation is therefore used at the early stages.

A pentest can be applied in situations such as:

- a major release,
- a critical change,
- a new application,
- an authentication change,
- a significant API change.

### \43. Why Is One Pentest a Year Not Enough?

Performing a pentest once a year on a continuously developed application can create a serious gap.

The pentest may have been done in January.

A new API is added in February.

Authentication changes in March.

A new payment module launches in April.

All these changes can remain untested until the next pentest.

A pentest must therefore be supported by continuous AppSec controls.

### \44. Which Security Controls Should Be Automated Within CI/CD?

These controls are generally suitable for automation:

- SAST
- SCA
- Secret Scanning
- Container Image Scanning
- IaC Scanning

DAST can also run automatically after deployment to the test environment.

A pentest continues as a separate, human-driven security activity.

### \45. How Should a Security Quality Gate Be Built?

A Quality Gate should not stop the build on every finding.

A risk-based policy is needed.

For example:

#### SAST

New critical injection → Block

#### SCA

Reachable critical CVE → Block

#### Secret

Active production secret → Block

#### DAST

Confirmed critical vulnerability → Release block

This policy should be customised to the organisation's risk appetite.

### \46. Should New Code and Legacy Code Be Managed the Same Way?

It may not always be possible.

Thousands of historic findings can exist in legacy applications.

Resolving them all at once may not be realistic.

In that case a:

#### New Code Policy

can be applied.

New code is not permitted to produce new critical and high security debt.

Old security debt is managed as a risk-based backlog.

**\47. Why Are SAST + SCA + Secret Scanning the Basic Trio?**

Because these three technologies cover three different code risks.

#### SAST

Is the code we wrote secure?

#### SCA

Is the code we use secure?

#### Secret Scanning

Did we leave an access key inside the code?

This trio is therefore a strong starting point in modern DevSecOps pipelines.

### \48. What Does DAST Add to This Trio?

DAST adds this question:

**"How does the code actually behave while running in a production-like environment?"**

This runtime perspective matters.

Because security can change on the way from code to deployment.

Configuration,

proxy,

server,

environment

behaviour can affect security.

### \49. What Does a Pentest Add?

A pentest adds this question to all these layers:

**"How would a real attacker abuse this system?"**

A pentester can therefore build attack scenarios instead of individual findings.

For example:

a low-severity information disclosure,

a medium-severity IDOR,

a weak reset flow

can combine to create a critical account takeover.

That creativity is an important advantage of human expertise.

### \50. Where Does Manual Code Review Fit in This Model?

Manual code review can act as a critical bridge between SAST and a pentest.

SAST shows the risky code areas.

The specialist examines the source code manually.

The pentest verifies the impact in the running application.

This model is strong particularly for critical applications:

**SAST → Manual Code Review → Pentest**

### \51. What Is a White Box Pentest?

During a white box pentest the security specialist may have access to more information, such as source code, architecture documents or user accounts.

This approach can increase test depth.

Source code access can be useful particularly when maximum security coverage in a short period is the goal.

The pentester can assess both application behaviour and code structure together.

### \52. What Is a Black Box Pentest?

In a black box pentest the specialist approaches the system from an external attacker's perspective.

There is no source code knowledge.

This approach is valuable for understanding the attack surface an external attacker could see.

But some code-level problems may stay invisible.

Different test approaches can therefore be used together for critical applications.

### \53. What Is a Gray Box Pentest?

In the gray box approach the pentester has limited internal information.

For example:

- a standard user account,
- API documentation,
- certain architectural information

can be provided.

This approach can strike a balance between a realistic attack scenario and testing efficiency.

### \54. Which Should an Organisation Start With?

This depends on the organisation's software maturity.

For an organisation with no AppSec controls at all, the start might be:

#### \1. Pentest

Make the existing real risks visible.

#### \2. SAST

Move code security to an early stage.

#### \3. SCA

Create dependency visibility.

#### \4. Secret Scanning

Reduce credential risk.

#### \5. DAST

Add runtime automation.

#### \6. DevSecOps

Integrate all the controls into the pipeline.

This ordering can change according to the organisation's needs.

### \55. The Recommended Model for a Small Software Team

A small team may not need to apply every enterprise security technology at once.

To start:

- Secure Coding
- SAST
- SCA
- Secret Scanning
- periodic pentesting

can form quite a strong foundation.

DAST and more advanced AppSec controls can be added as the application grows.

### \56. The Recommended Model for a Large Organisation

A more central structure is needed in large organisations with many applications and developers.

For example:

- an AppSec platform
- SAST
- SCA
- Secret Scanning
- DAST
- API Security
- SBOM
- Central Vulnerability Management
- Security Champions
- a Pentest Programme
- Secure Coding Training

can be used together.

The most important matter here is not the number of tools but process integration.

### \57. What Should the Model Be in Finance and Critical Systems?

Because risk is higher in financial and critical systems, additional manual controls can be recommended.

For example:

#### SAST

#### SCA

#### Secret Scanning

#### Manual Code Review

#### DAST

#### API Pentest

#### Web Pentest

#### Threat Modeling

can be used together.

Authentication, authorisation and financial transaction logic in particular should be examined deeply by hand.

### \58. Does Increasing the Number of Tools Increase Security?

Not always.

Using ten different security tools does not automatically create a good AppSec programme.

If:

- findings are not managed,
- the same findings recur,
- they do not reach developers,
- SLAs are not tracked,
- false positives are not cleaned up

then the number of tools can only increase operational noise.

Successful AppSec is a balance of:

**Tool + Process + People**

### \59. Should a Single AppSec Platform Be Used?

Unified AppSec platforms can offer different controls such as:

- SAST,
- SCA,
- Secret Scanning,
- IaC scanning

in one place.

That can provide a central visibility advantage.

But when choosing a product, the real technical capability of every module should be assessed.

Using a single platform provides operational convenience, but technical adequacy should not be assumed merely because it is a single platform.

### \60. Should Findings Be Collected in One Central Place?

Yes, particularly in large organisations this is useful.

Findings from different tools:

- can be duplicates,
- can use different severities,
- can report the same flaw in different ways.

Centralized Vulnerability Management can normalise these results.

The total risk per application can then be seen.

### \61. How Should a Security Finding Be Prioritised?

Whatever its source, these factors can be used together in a real risk assessment:

- Severity
- Exploitability
- Reachability
- Internet Exposure
- Data Sensitivity
- Business Criticality
- Known Exploitation
- Existing Controls

Decisions are then not made on the tool's score alone.

### \62. Are a SAST Critical and a Pentest Critical the Same Thing?

Not always.

Different tools and methodologies can use different criteria when determining severity.

SAST can produce a theoretical critical, but the code may not be reachable.

A pentest can report a critical finding with verified exploitation.

Severity normalisation is therefore important.

### \63. Where Is CVSS Used?

CVSS can be useful in assessing the technical severity of a vulnerability.

But an enterprise risk model should add business criticality and asset context on top of CVSS.

For example:

**CVSS + Asset Criticality + Exposure + Exploit Intelligence**

can provide more realistic prioritisation.

### \64. How Do AppSec Findings Enter the Developer Backlog?

Security systems can be integrated with Jira, Azure DevOps or similar work-tracking systems.

A verified finding can be assigned automatically to the relevant repository owner.

The ticket can contain:

- the risk,
- the affected code,
- the remediation,
- the SLA,
- the evidence.

This approach prevents the security report being forgotten inside a PDF.

### \65. Who Should Perform the Retest?

Whether the finding has genuinely been closed must be verified after remediation.

An automatic re-scan may be sufficient for a SAST finding.

But a business logic flaw found by a pentest requires a manual retest.

The retest method should therefore be chosen according to the finding type.

### \66. What Is Security Regression?

A previously fixed vulnerability reappearing can be called security regression.

A developer has fixed an SQL Injection, for example.

Months later another developer adds a similar insecure pattern again.

An automated test rule should therefore be created after remediation where possible.

CI/CD can then catch the problem if it reappears.

### \67. Can a Pentest Finding Be Turned into a SAST Rule?

In some cases yes.

This is a highly valuable indicator of AppSec maturity.

Insecure use of a function specific to the organisation's own framework is detected during a pentest, for example.

The AppSec team creates a custom SAST rule.

From then on, the same pattern is detected automatically when it appears in another repository.

This model is the:

#### Turning a manual finding into an automated control

approach.

### \68. Secure Coding Training After a Pentest

If the same vulnerability types recur in pentest reports, developer training can be designed around those real findings.

If the organisation keeps producing BOLA problems, for example, dedicated Secure Coding training on API authorisation can be delivered.

A pentest then does not only find vulnerabilities.

It provides data for the organisation's development.

### \69. How Does AppSec Maturity Develop?

An entry-level organisation:

**performs one pentest a year.**

At the next level:

**it adds SAST.**

Then:

#### SCA + Secret Scanning

are added.

Later:

#### DAST + DevSecOps

are built.

And in a mature structure:

**Threat Modeling + Security Champions + Metrics + Continuous AppSec**

come into play.

Security turns from a test into a programme.

### \70. Comparing SAST, DAST, SCA and Pentest

In summary:

#### SAST

#### What does it look at?

Source code.

#### When?

At the development stage.

#### Advantage?

Early detection and code-line visibility.

#### Limitation?

Runtime and business logic.

#### DAST

#### What does it look at?

The running application.

#### When?

In the test/staging environment.

#### Advantage?

Real runtime behaviour.

#### Limitation?

Cannot see the source code.

#### SCA

#### What does it look at?

Open source and third-party dependencies.

#### When?

In build and dependency management.

#### Advantage?

CVE and component visibility.

#### Limitation?

Does not analyse the application's own code or business logic.

#### Pentest

#### What does it look at?

The real attack surface.

#### When?

Before release or periodically.

#### Advantage?

Human creativity, business logic and attack chaining.

#### Limitation?

Time and scope are limited.

### \71. The Ideal Application Security Flow

An example flow for a modern organisation might be:

#### Developer

↓

#### Secure Coding

↓

#### Commit

↓

#### Secret Scanning

↓

#### SAST

↓

#### SCA

↓

#### Build

↓

#### Security Quality Gate

↓

#### Test Environment

↓

#### DAST

↓

#### Manual Pentest

↓

#### Production

↓

#### Continuous Monitoring

This model takes security out of being a final check.

It distributes it across the whole software life cycle.

### The SecureSys Application Security Approach

At SecureSys we do not treat the SAST, DAST, SCA and pentest approaches as alternatives to one another.

Each makes a different attack surface and a different security risk visible.

In line with project and application criticality, the layers:

#### SAST, SCA, Secret Scanning, DAST, API Security Testing, manual source code analysis and pentesting

can be assessed together.

In critical applications in particular, the goal is not merely to run an automated scan;

**it is to combine the code, dependency, runtime and attacker perspectives into a single security picture.**

SAST may be clean on an application.

But a business logic flaw may be present.

A pentest may go well.

But an active production secret may be present in the source code repository.

DAST may produce no critical findings.

But an actively exploited CVE may be present inside a dependency.

The right question is therefore not:

**"Which security product are we using?"**

The real question should be:

**"Which security risks can we actually see?"**

The aim of the modern Application Security approach is not to load all security onto one tool;

**it is to have different controls close one another's blind spots.**

### Frequently Asked Questions

#### What is SAST?

SAST is the Static Application Security Testing method that analyses an application's source code from a security perspective without running it.

#### What is DAST?

DAST is the Dynamic Application Security Testing method that tests the running application dynamically from outside.

#### What is SCA?

SCA is the Software Composition Analysis method that analyses the open source and third-party dependencies used in an application for vulnerabilities and licence risks.

#### What is a pentest?

A pentest is the assessment of a system's security by specialists using scenarios as close as possible to real attacker behaviour.

#### What is the difference between SAST and DAST?

SAST analyses source code, while DAST tests the running application from outside.

#### Are DAST and a pentest the same thing?

No. DAST is automated dynamic scanning. A pentest is a more comprehensive test in which a security specialist manually assesses the application's business logic and attack surface.

#### Does SAST replace a pentest?

No. SAST provides a source code perspective, while a pentest provides a real attacker's perspective on the running system.

#### Why is SCA necessary?

Because modern applications use a large number of third-party dependencies, the security risks of code the organisation did not write must also be made visible.

#### Which is better: SAST or DAST?

They are not alternatives to one another. SAST provides security visibility at code level, DAST at runtime level.

#### What is the strongest Application Security approach?

It is the layered model in which SAST, SCA, Secret Scanning, DAST, manual source code analysis and pentesting are used together according to application risk.

### Conclusion: The Best Security Test Is Not a Single Test

One of the mistakes made often in the Application Security world is loading too much meaning onto a single technology.

When SAST is purchased, the code may be thought entirely secure.

When DAST is run, the application's whole attack surface may be assumed checked.

When SCA is used, dependency risks may be thought completely resolved.

And when a pentest is done, the application may be assumed to stay secure until the next test.

In reality none of these is sufficient on its own.

Because modern applications do not consist of a single layer.

There is the code we wrote ourselves.

There is the third-party code we use.

There is the runtime environment.

There are APIs.

There are user roles.

There is business logic.

There is the CI/CD process.

And there is the attacker trying to abuse all of it.

Therefore:

**SAST sees the code.**

**SCA sees the dependencies.**

**DAST sees the running application.**

**The pentest tries to see what an attacker could do.**

When these four perspectives come together, security visibility becomes far stronger.

And that is exactly the aim of modern Application Security:

**not to see everything with a single tool, but to ensure no critical area stays invisible.**