Dealing with application vulnerabilities: best practices for security testing

Addressing the growing scope and sophistication of vulnerabilities requires a multi-modal testing approach. A layered testing strategy that combines various methodologies ensures that as many risks as possible can be identified and addressed as early as possible across every phase of the SDLC. Some traditional approaches include:

1. Static Application Security Testing (SAST): Solutions focus on analyzing source code to identify vulnerabilities early in the development process without executing code, making them effective tools for catching flaws such as logic errors, insecure coding practices, and syntax issues before deployment. By seamlessly integrating into developer workflows, SAST can help promote secure coding from the outset while supporting continuous testing in CI/CD environments.

However, SAST solutions have their limitations. They do not identify runtime vulnerabilities or issues tied to third-party libraries and can generate high numbers of false positives, which can frustrate development teams and slow down the pipeline if not carefully managed. This results in extra manual effort to validate and prioritize remaining bugs/vulnerabilities.

2. Dynamic Application Security Testing (DAST): Solutions operate on live (production or simulated live/staging) applications, simulating real-world attack scenarios to uncover security risks that manifest during runtime. DAST excels at identifying vulnerabilities tied to application logic, external integrations, and runtime-specific interactions, making it an essential layer in security testing.

However, because it focuses on runtime behavior, DAST cannot address vulnerabilities embedded in the source code, and often requires expertise with tedious configuration and tuning to avoid gaps in test coverage or suboptimal results. Despite these challenges, DAST remains a powerful tool for real-world vulnerability assessment.

3. Penetration testing: Penetration testing shines in its ability to provide deep human-led, contextual analysis of an application's vulnerabilities, leveraging skilled professionals to simulate targeted attacks. This often very manual approach is invaluable for identifying sophisticated threats missed by automated tools alone. It helps map and verify vulnerabilities, delivering actionable findings with minimal false positives.

Nonetheless, the resource-intensive nature of penetration testing often limits its frequency, making it more suitable for periodic or targeted assessments rather than continuous testing. Despite these constraints, penetration testing remains a critical component for any organization's app and API security efforts.

There are also many emerging security testing solutions that can complement these traditional methods. These include techniques like fuzz testing, Interactive Application Security Testing (IAST), Runtime Application Self-Protection (RASP), and AI-augmented testing that leverages machine learning to prioritize vulnerabilities, detect anomalies, and streamline the testing process.

Together with traditional methods, these newer approaches help organizations tackle the evolving complexity and risks of today's application ecosystems. Organizations should see them as additional tools that can be layered together as part of their app and API security posture throughout the SLDC to keep up with ever-evolving app and API threat landscapes.