Kubernetes, microservices, low/no-code platforms, and AI-driven tools like GitHub Copilot have created a labyrinth of interconnected systems. Each new API, service, or line of code adds complexity to web applications, which are rapidly increasing in both scale and intricacy. All this means one thing—the average organization's attack surface has grown out of control.
Attackers look to exploit every possible weakness they can find - and often, they don’t need to look too hard. 61% of web applications are affected by critical vulnerabilities. When left unpatched, these vulnerabilities cause 60% of all data breaches. As a security leader, you need a keen grasp of your web applications’ security posture.
Web application penetration testing is a series of simulated attacks or tests on a web application to compromise security and gain privileged access to its backend or sensitive information. Also called ethical hacking, these tests may be automated using tools or manually performed by humans. They imitate an attacker’s behavior and look to detect and mitigate vulnerabilities across the attack surface.
These are the key steps in the process of web application pen testing:
The pen testing process can take anywhere from a few days to several weeks or even months, depending on the complexity of the web applications, the tools and teams involved, and the scope of the testing. As a result, companies perform pen testing infrequently - often once a year or as mandated by regulations - assuming that once the tests are completed, the application remains secure and compliant for several months.
However, this approach is outdated. As security needs to evolve alongside continuous integration and delivery (CI/CD) practices, pen testing must shift towards a more continuous, proactive model.
The OWASP Top 10 is the industry standard for ranking the highest-priority web application vulnerabilities, which include:
Access control defines who (or which services) can access any part of a web application. When this is broken, it’s like leaving the doors open for anyone to enter. Security researchers discovered a vulnerability in Salesforce that enabled an account takeover due to broken access controls. A misconfigured password controller allowed anyone to access an account using a reset password option.
Cryptographic failures occur when secure encryption methods are not adequately applied to sensitive data, such as personally identifiable information (PII). This failure can lead to the theft of valuable data from customers or an organization. For example, HPE (HP Enterprise) was recently the victim of a breach that exposed its internal code repositories, security certificates, Docker builds, and API access keys due to cryptographic failures.
Injection attacks occur when a bad actor sends malicious code into a system to compromise defenses and steal sensitive data. Cross-site scripting (XSS) and SQL are common injection attack types, affecting even tech giants like AWS.
Web application architecture plays a key role in security. Organizations should follow the default of secure code-by-design. Though security best practices are well-known, organizations fall short in implementing them. Paying attention to web application design is crucial to preventing cyber attacks.
Tools like Terraform, AWS CloudFormation, and Helm charts make it easy to apply configuration across the entire cloud infrastructure at scale. However, when misconfiguration occurs, they can perpetuate just as quickly. Examples of security misconfigurations are frequently found in the news.
The remaining OWASP Top 10 vulnerabilities include vulnerable and outdated components like Zombie IT, identification and authentication failures through weak or compromised methods, software and data integrity failures in third-party tools and pipelines, security logging and monitoring failures due to outdated solutions, and server-side request forgery (SSRF), where attackers intercept remote requests.
Though the official list is set for an update in the first half of 2025, these OWASP Top 10 vulnerabilities are still critical and must remain a focus for security leaders.
As you craft a pen-testing strategy for your web applications, there are too many bases to cover. But by following these principles, you can significantly improve your web application’s security posture and reduce the number of potential exploits at any given time.
When doing pen testing, clarity is essential to ensure your efforts are not wasted. Define which exact assets you’ll put under test, what conditions you’ll test them for, whether you have a clear end goal, or whether your pen testing is more exploratory.
Ensure the assets and applications you want to test align with your organization’s highest-risk areas. Clearly define the conditions and attack vectors—whether you’re simulating external or internal threats, testing specific vulnerabilities, or evaluating response protocols. Lastly, establish measurable goals—from assessing compliance, detecting weaknesses, or testing incident response capabilities—so you can track results.
Pen testing, when done as a one-off, offers limited value. For it to be truly effective, it must be continuous or frequent at a minimum - running tests consistently throughout the year. While this may seem overwhelming, automated pen testing tools simplify the process. These tools have limitations, too, so it’s important to consider key features like context-aware testing and comprehensive coverage when choosing a pen testing tool for your systems.
Many code scanning (SAST) tools are available today that easily spot vulnerabilities and exposures in application code. These tools are based on automated rules and are powerful enough to spot an exposure even among thousands of lines of code or hundreds of microservices.
To enhance automated scanning, use context-aware tools that understand code dependencies and configurations, reducing false positives. Integrate SAST with DAST (Dynamic Application Security Testing), which simulates real-world attacks to uncover vulnerabilities during execution. This combination ensures you cover both static code and runtime behavior. Additionally, incorporate dependency management tools to secure third-party libraries and components, reducing vulnerabilities in your application stack.
With the rise of AI technologies, pen testing can surpass traditional, rules-based scanning to simulate human-like awareness and testing. AI-driven pen testing can proactively identify vulnerabilities in ways that static rules cannot, adapting to new threats in real-time. This approach not only enhances detection accuracy but also uncovers complex vulnerabilities that might be missed by manual testing or conventional automated scans.
Knowing how many vulnerabilities exist in your web application is not enough; you also need to understand their exploitability and broader business context. Risk-based prioritization will help you focus your efforts, avoid time waste, and ensure critical vulnerabilities are addressed promptly. Terra’s Agenic AI platform leverages AI models to assess the actual risk of each vulnerability based on context, attack vectors, and real-world exploitability, helping teams prioritize their efforts and reduce false positives.
Gone are the days of relying on open-source tools and outdated commercial pen testing solutions. While some offer dynamic testing (DAST), they are often noisy, riddled with false positives, lack customization, and fail to address complex attack scenarios effectively. These solutions become obsolete from the moment they are run. Instead, it’s time for a new approach to pen testing - one that is Agentic-AI-based, faster, more accurate, and more comprehensive than humans.
Unlike traditional tools, Terra’s Agentic-AI platform offers continuous, context-aware pen testing that evolves with your systems. With a human-in-the-loop mechanism, Terra ensures reliability with AI and focuses the manual work on the highest priority areas. The test plan adapts in real-time, performing thousands of tailored tests for comprehensive attack surface coverage. This combination of AI-driven intelligence and human oversight ensures speed and precision while addressing unique business risks.
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