Ensuring PCI DSS Compliance: The Role of SAST, DAST, and API Security Testing

Every swipe, click or tap carries a silent promise: your payment data is safe. PCI DSS isn’t just a regulatory box to tick—it’s the gold standard for safeguarding that promise. When customers entrust you with their payment details, they’re not just handing over data; they’re handing over their confidence. For financial institutions, PCI DSS compliance isn’t optional. It’s the price of entry to an industry built on trust, security, and unshakable reliability.

But let’s be honest—staying compliant is no walk in the park. Attackers evolve by the minute while application security teams scramble to keep up with sprawling systems and shifting vulnerabilities. PCI DSS compliance isn’t something you “set and forget.” It’s a relentless, all-hands-on-deck commitment to fortifying sensitive data at every turn. Because in this game, “good enough” security is never good enough.

Understanding PCI DSS requirements

Protecting payment card information is vital for any organization that handles it. To help with this, the Payment Card Industry Data Security Standard (PCI DSS) sets a baseline of rules and safeguards that must be implemented to protect this data from breaches and fraud. These rules cover every stage of the lifecycle of cardholder data, covering everything from how to build secure systems to operational steps like monitoring and testing.

These requirements serve as a mandatory roadmap for organizations; however, they are much more than that. They are also a method of building consumer trust, knowing that their data is well protected by the merchants they use. Those who fail to comply will eventually have their ability to process payment cards revoked, so organizations can't slip by in the long by paying the fines but maintaining poor practices.

Compliance with PCI DSS also helps organizations set a security baseline, an essential step in addressing the constantly evolving threats they face. It creates a foundation for organizations to build more targeted controls to better secure their infrastructure.

Challenges in achieving PCI DSS compliance

For most organizations, achieving compliance is no small task. Modern IT organizations span on-premises hardware, virtualized systems, and cloud components. Anywhere that payment card data may lie or traverse becomes part of the scope of PCI DSS. This may include custom applications, databases, servers, and the networks that connect them. Locating and assessing these areas can be a monumental task, especially for compliance teams that are frequently spread relatively thin.

Modern applications further complicate compliance efforts. The reliance on microservices, APIs, and third-party libraries creates a sprawling attack surface that can be difficult to secure. Each component introduces its own set of vulnerabilities, and ensuring that every layer adheres to PCI DSS standards requires meticulous attention to detail and significant resources. This complexity amplifies the risk of misconfigurations or overlooked vulnerabilities, threatening the organization’s compliance posture.

Another significant challenge is integrating security into the development lifecycle. The drive to deliver features quickly often deprioritizes security, resulting in gaps in secure coding and testing practices. Disconnected tools and manual workflows further exacerbate the problem, making enforcing consistent security measures across teams and processes difficult. Without a unified approach, organizations struggle to maintain compliance while keeping up with the demands of modern software development.

Navigating these challenges requires more than a checklist approach. It demands a strategic alignment of processes, tools, and people to seamlessly embed security and compliance into every application development stage.

Best practices for PCI DSS compliance

It takes more than just a single step to achieve compliance. It requires a multifaceted approach, best practices, and operational strategies to create in-depth application security. Here are key best practices to guide financial institutions in safeguarding payment data and adhering to these critical standards:

Secure development practices

Incorporate security into the development process to start with a strong foundation. Static Application Security Testing (SAST) tools build this foundation by identifying vulnerabilities in code, such as injection flaws or hardcoded credentials. These tools pair well with those that analyse third-party libraries, helping ensure that the components that make up an application do not import vulnerabilities.

Comprehensive testing

Expand your security checks beyond code with runtime testing. Dynamic Application Security Testing (DAST) identifies vulnerabilities in live web applications, uncovering risks that static testing might miss. For APIs, assessments should focus on proper authentication, encryption, and rate limiting to secure endpoints against threats.

Encryption and data protection

PCI DSS requires payment data to be encrypted both in transit and at rest. Encryption protocols must be configured appropriately and validated using security tools that can detect potential weaknesses. Robust encryption prevents sensitive data from being intercepted or exposed.

Monitoring and logging

Implement advanced logging and monitoring systems to maintain visibility into application activity. Comprehensive logs and real-time alerts allow quick detection and response to suspicious behavior, reducing the potential impact of breaches.

Regular updates and patching

Maintain a proactive approach to updating frameworks, libraries, and systems. Regular patching ensures your organization is protected against known vulnerabilities, a fundamental requirement of PCI DSS compliance. Keeping your stack current minimizes exposure to threats.

The role of security testing in PCI DSS compliance

Much of the compliance effort for PCI DSS involves proving that the controls are in place and working. By using testing tools consistently teams can identify vulnerabilities across their applications and create a paper trail of documentation to show a record of consistent compliance. This documentation evidence makes it easy for auditors to check that testing happens every time.

SAST: Secure code from the start

The foundation of application security starts with the code, and this is where SAST shines in identifying coding vulnerabilities early in development. Issues like injection flaws, hardcoded credentials, or weak input validation can be flagged before the code leaves the developer’s hands. When integrated with CI/CD pipelines, SAST ensures continuous compliance, providing real-time feedback during each build and empowering teams to fix vulnerabilities early on while they’re still inexpensive and easy to address.

DAST: Protecting live applications

Applications are more than the code they run on. The moment an application starts, it has a broader attack surface that encompasses the systems it runs on and how it interacts with them. DAST bridges this gap by simulating real-world attack scenarios against running applications. This testing method uncovers and validates the effectiveness of security controls, unearthing more complex vulnerabilities such as weak session handling, insecure authentication, and misconfigured encryption that can only be discovered when the application runs.

API security testing

APIs are integral to modern financial systems, yet they often introduce unique vulnerabilities. Dedicated API security testing evaluates endpoints for compliance with PCI DSS standards, focusing on critical areas like proper authentication, encryption protocols, and rate limiting. By identifying misconfigurations or data exposure risks, API testing ensures that these essential components don’t weaken your security posture.

Automated reporting

Documentation is a significant part of PCI DSS compliance, and manual reporting can be tedious and error-prone. Automated tools like Snyk simplify this process by generating audit-ready compliance reports. These reports provide clear, detailed evidence of testing efforts, streamlining audits, and helping organizations maintain a transparent compliance record.

Benefits of an integrated approach with Snyk

PCI DSS compliance isn’t a box to check, it’s a battle plan for securing trust. Achieving it takes more than good intentions and surface-level fixes. Enter Snyk: a seamless, end-to-end solution designed to address vulnerabilities at every stage of the application lifecycle.

Here’s how it works:

• SAST ferrets out flaws in proprietary code before they become problems.

• DAST exposes runtime vulnerabilities lurking in live environments.

• API security testing locks down endpoints, staying one step ahead of evolving threats.

• Bonus: Snyk Learn helps organizations meet compliance goals with NIST NICE-aligned lessons and the possibility to download completion reports.

Together, they deliver airtight coverage that leaves no weak links in your application’s defenses.

But here’s the kicker: compliance doesn’t have to slow you down. By automating scans and embedding them directly into CI/CD pipelines, Snyk ensures continuous monitoring without throwing a wrench into your development workflows. Developers get precise, actionable insights with step-by-step remediation guidance, with no guesswork, and no delays. Continuous testing keeps your systems compliant as they grow and evolve, turning PCI DSS compliance into an ongoing advantage, not a one-time headache.

With Snyk, financial institutions can safeguard sensitive data, outsmart attackers, and innovate confidently, all while maintaining the trust that keeps customers coming back. 

Want to learn more about how Snyk can help you stay compliant with PCI DSS standards? This cheat sheet simplifies the process, offering actionable insights on how Snyk can help your organization. Download your free copy today.