Your organization, the industrial domain you survive on, and almost everything you deal with rely on software applications. Be it banking portals, healthcare systems, or any other, securing those applications is paramount. Application Security Testing is the process of making applications more resistant to cyber threats by identifying weaknesses and vulnerabilities in the code. In practice, it is a set of processes and tools that help development teams detect and address security gaps early in the software development lifecycle. By integrating AppSec into the development process, often called “shift-left” security, organizations can catch issues before deployment, avoiding the costly damage of discovering vulnerabilities after an application is live. As a matter of fact, the application layer is now one of the most attacked and hardest-to-defend parts of the enterprise stack, which is why the global AST market is valued at over $33 billion. 

Why Does Application Security Testing Matter to Every Business? 

Effective application security testing delivers broad benefits across industries:

• Protect Sensitive Data: Applications often store personal, financial, or business-critical data. Testing helps prevent breaches that could lead to identity theft or financial loss.
• Maintain Customer Trust: Users expect their information to be safe. A single security incident can damage your reputation and erode client confidence.
• Ensure Business Continuity: Attacks on applications can disrupt services. Secure apps help avoid downtime and lost revenue by keeping operations running smoothly.
• Meet Compliance Requirements: Many industries (finance, healthcare, etc.) are subject to regulations like GDPR, HIPAA, or PCI-DSS. Regular appsec testing helps ensure compliance and avoid legal penalties.
• Reduce Remediation Costs: Fixing vulnerabilities early (during development) is far cheaper than after deployment or after a breach.
• Defend Against Evolving Threats: Cyber threats constantly evolve. Continuous testing keeps applications resilient against new attack methods.

Application Security Testing was never a yearly task; it’s an ongoing part of the software lifecycle. Without going through the already-known information, let’s explore the key types of application security testing that you need to know about to secure your application software:

Web Application Security Testing

OWASP highlights one core aspect, Web Application Security Testing, which often involves penetration testing of web apps. This is a methodical, active analysis of a web application to find any weaknesses, technical flaws, or vulnerabilities. Skilled security testers emulate real-world attacks on the application, for example, attempting SQL injections, XSS, authentication bypasses, and more. Subsequently, they present the findings to the application users/owners along with impact assessments and remediation recommendations.

Web appsec tests can be performed in different ways depending on the knowledge given to the tester. 

• In black-box testing, the tester has no internal knowledge of the system, mimicking an external attacker’s perspective. This approach is great for discovering security issues visible to outsiders, including configuration mistakes or vulnerabilities in exposed interfaces
• White-box testing gives the tester full access to the source code and architecture, allowing a thorough audit of the application’s inner workings. White-box tests can uncover deep flaws like logic errors or insecure cryptography early in development by combining techniques such as code review, static analysis, and even threat modeling. 
• Many engagements use a grey-box approach, where some knowledge is provided to balance depth and efficiency. 

What you can do? Following established methodologies like the OWASP Web Security Testing Guide helps ensure the testing process is consistent, reproducible, and rigorous, covering areas from input validation to authentication, session management, and more.

Mobile Application Security Testing

Mobile applications seem to be everywhere across industries. You can think of banking apps, retail apps, healthcare apps, etc. and with them follows the unique security challenges. Mobile Application Security Testing adapts web testing techniques to the mobile environment. It typically combines static analysis, dynamic analysis, and even forensic methods to evaluate a mobile app’s security. Just like with web apps, testers will examine the mobile app’s code and behavior for vulnerabilities, but they also look at mobile-specific issues. 

For example, a mobile security test will check for problems like insecure data storage on the device, hardcoded credentials in the app, weak encryption, or the ability to bypass protections via jailbreaking/rooting. 

Mobile appsec testing also considers the app’s interaction with device features and networks; for instance, does the app securely handle data over Wi-Fi or cellular networks? Does it properly restrict access to sensitive resources like the camera or file system? A thorough mobile security testing process can uncover vulnerabilities such as insecure API calls, insufficient authentication, or data leakage specific to mobile environments. Given the popularity of mobile apps, robust mobile application security testing is essential across industries, ensuring that your customer-facing app or internal mobile tool doesn’t become an entry point for attackers.

Static Application Security Testing (SAST)

When developers hear “shifting security left,” Static Application Security Testing is often the first technique that comes to mind. SAST tools analyze an application’s source code or compiled code without executing it, to spot vulnerabilities early in development. This is a white-box testing approach where the scanner has full visibility into the code. 

A SAST scan will comb through the codebase looking for dangerous coding patterns and flaws, for example, missing input validation, insecure use of APIs, hard-coded secrets, or error-prone logic that could lead to security bugs. Essentially, SAST tries to catch issues like SQL injection vulnerabilities, buffer overflows, or improper error handling by inspecting the code itself before the application ever runs.

One advantage of SAST is that it can be integrated directly into the development workflow. Developers can run static analysis in their Integrated Development Environment (IDE) or as part of continuous integration (CI) pipelines, getting quick feedback on security issues in their code. 

Modern SAST-supporting tools come with extensive rule sets with AI enhancements to detect common weaknesses and reduce false positives, making them much faster than manual code reviews for finding known vulnerability patterns. By catching bugs early, SAST helps teams fix issues long before they reach production, which, as mentioned, significantly lowers the cost and impact of remediation.

Dynamic Application Security Testing (DAST)

While SAST looks at static code, Dynamic Application Security Testing takes a black-box approach by evaluating the application in its running state. DAST involves executing the web or mobile application, typically in a testing environment, and probing it from the outside, much like an external attacker would. 

The DAST tool or tester does not need access to the source code; instead, it interacts with the application’s interfaces like web pages, APIs, etc., sending various inputs and payloads to detect security weaknesses at runtime.

DAST is excellent at finding issues that only manifest when the app is running. It can also uncover misconfigurations and errors in how the app handles sessions, cookies, or authentication flows. Essentially, DAST simulates real attack patterns, from fuzzing inputs with random data to performing login and authorization bypass attempts, and watches how the application responds. Because DAST requires a working application, it often comes into play later in the development cycle during QA or staging deployments. However, it’s a crucial complement to SAST. 

Whereas SAST might tell you “there could be a SQL injection if this code is exploitable,” a DAST test will actually attempt the SQL injection on a running app to confirm if the vulnerability is present. In practice, using both SAST and DAST in tandem provides a much more comprehensive view of security. SAST finds the potential flaws inside the code, and DAST shows the actual weaknesses visible from outside – together helping ensure nothing falls through the cracks.

Software Composition Analysis (SCA)

Modern applications are built not only on custom code, but also on a foundation of third-party components and open-source libraries. Software Composition Analysis (SCA) focuses on these external components. SCA tools help organizations inventory all the open-source and third-party packages in their software and check them for known vulnerabilities. This is crucial because an enterprise application might include thousands of such components – any of which could have publicly disclosed security flaws or outdated versions.

An SCA scan will typically produce a “bill of materials” listing all libraries/dependencies in an application, along with their versions. It then cross-references this list against databases of known vulnerabilities like the CVE database to flag if, say, your app is using version 1.2.3 of Library X, which has a critical security bug. SCA not only identifies these vulnerable components, but often provides information on severity and even suggested fixes or newer, patched versions. 

High-profile incidents like the Log4j and Spring4Shell vulnerabilities have taught everyone that you must know what’s inside your software. 

Threat Modeling

“What are we building, what can go wrong, and what should we do to prevent or mitigate those scenarios?” During threat modeling, security architects and developers map out the application’s components such as modules, data flows, entry points, and trust boundaries and then brainstorm possible threats or abuse cases for each. 

For example, if you’re developing an e-commerce web app, a threat model might consider scenarios like “What if an attacker intercepts data between the frontend and backend?”, “What if an insider tries to escalate privileges?”, or “How could someone exploit this third-party payment API?” For each identified threat, the team assesses the impact and likelihood, then plans mitigations like adding encryption, input validation, extra authentication checks, etc. The value of threat modeling is that it guides you to build security into the design from the very beginning, rather than reacting to issues later. 

Comprehensive Application Security Testing Solutions: Manual Expertise + Automated Scanning

As we’ve seen, securing applications requires a multifaceted approach. No single tool or test can catch everything. The most effective programs combine expert manual testing with smart automated tools. For example, manual penetration testing and threat modeling bring human creativity and contextual understanding, while SAST/DAST scanners and SCA tools provide speed and breadth of coverage.

Kratikal offers a full suite of Application Security Testing services to cover all these bases. Our manual appsec services include:

• Web Application Security Testing – Expert-led penetration testing of your web apps using OWASP methodologies to find logic flaws and vulnerabilities that automated scans might miss.
• Mobile Application Security Testing – In-depth testing of mobile app binaries and backends, identifying weaknesses unique to mobile environments like insecure storage, API vulnerabilities, etc.
• Software Composition Analysis – Auditing your software’s third-party components for known vulnerabilities and compliance issues, with guidance to patch or upgrade risky libraries.
• Threat Modeling – Facilitated workshops and analyses to map out potential threats to your applications early in the design phase, ensuring security by design.
• Static (SAST) & Dynamic (DAST) Testing – Thorough code review and automated scanning to pinpoint security weaknesses in source code and in running applications, respectively, before attackers can.

Through our product AutoSecT, we also provide automated Application Vulnerability Management to continuously secure your software between manual test engagements. AutoSecT offers continuous scanning for your web and mobile applications, integrating both SAST and DAST capabilities into a unified platform. This means it can automatically scan your application’s source code and binaries for flaws and regularly probe your running applications for emerging vulnerabilities, all on an ongoing basis. 

Wrapping Up

Do you think Application security testing is still about “finding bugs”? No, it’s majorly about defending the business logic that keeps your organization running. Every application today carries customer data, revenue flows, and operational trust, making it a prime target regardless of industry. A resilient application security testing program doesn’t rely on tools alone or annual audits; it blends attacker-level thinking, continuous validation, and real-world exploitation testing. By combining deep manual expertise with automated application security intelligence, organizations uncover what scanners miss and prioritize what actually matters. Our testing services, powered by AutoSecT, help security and engineering teams stay ahead of attackers not by slowing releases, but by embedding confidence into every deployment. When security works quietly in the background, innovation stops being a risk and starts being an advantage.

The post What is Application Security Testing? Detail Explanation appeared first on Kratikal Blogs.

*** This is a Security Bloggers Network syndicated blog from Kratikal Blogs authored by Puja Saikia. Read the original post at: https://kratikal.com/blog/what-is-application-security-testing-detail-explanation/