Information Security Testing: A Complete 2026 Guide & Best Practices

As the world becomes increasingly digital, small and mid‑sized businesses rely heavily on web and mobile applications to manage operations, drive revenue, and serve customers. With this reliance comes heightened risk. Cyberattacks are becoming more sophisticated, and data breaches are more costly than ever. Application engineers, designers, and developers are now focused on building secure application architectures and writing secure code from the outset.

To create a truly secure application, you need a solid process for information security testing. This comprehensive 2026 guide explains what information security testing is, why it is critical, the key types of testing, and best practices for integrating security into your development lifecycle.

For a broader view of security testing in specific domains, read our guide on API Security Testing: Rules, Checklist & 2026 Best Practices.

What Is Information Security Testing?

Information security testing is the practice of evaluating platforms, services, systems, devices, applications, and processes for security vulnerabilities. It often involves automated tools that scan for known vulnerabilities and simulate attacks using recognised threat patterns. It may also include manual attacks conducted by skilled information security professionals.

The ultimate purpose of security testing is to answer critical questions:

• Is the application vulnerable to known threats?
• Does the system protect data while maintaining functionality?
• Is there any risk of data leakage?
• How does the application behave when faced with a malicious attack?

Security testing is partly a subset of functional testing—some basic security checks belong in functional test suites. However, security testing should also be planned and executed independently. Unlike functional testing, which verifies expected behaviour, security testing focuses on the unexpected, exploring the infinite ways an application could be exploited.

For a related topic on securing mobile apps, read A Checklist Every Developer Must Have For Mobile App Security Testing.

Why Is Information Security Testing Important in 2026?

A comprehensive security testing strategy maintains control over all layers of an application: the code, the network, the database, and the presentation layer. While application and mobile testing evaluate security at the user level, cloud penetration testing reveals security gaps when the application is hosted in the cloud.

In today’s interconnected world, where consumers rely heavily on online channels to transact, any security threat—no matter how minor—can lead to loss of customer confidence and ultimately revenue. Security threats have also grown exponentially, both in severity and in the range of potential attack vectors.

Information security testing provides critical value to organisations:

To understand how security testing fits into a broader QA strategy, read 7 Tips for Developing the Ultimate Test Automation Strategy.

How to Start with Information Security Testing

Integrating security testing into the development process is essential for uncovering application‑layer security flaws. Security testing should begin as early as the requirements collection stage to understand the security requirements of the application.

Security Testing Lifecycle

Shifting security left—starting early—significantly reduces the cost and effort of fixing vulnerabilities compared to discovering them in production.

For a detailed security checklist, read Cyber Security Testing Checklist: 9 Essential Steps for Product Security.

Key Types of Information Security Testing

To build a secure application, security testers need to conduct a combination of automated and manual tests.

1. Vulnerability Assessment (Scanning)

A vulnerability assessment scans the entire system under test to identify vulnerabilities, oversights, and suspicious weak signatures. This scan identifies and characterises system weaknesses and also forecasts the effectiveness of countermeasures that have been implemented.

2. Penetration Testing (Pen Test)

A penetration test, or pen test, is a simulated attack that follows the methodology of a hacker. It involves gathering information about the system, understanding entry points, and attempting a break‑in to determine security weaknesses.

Types of penetration testing:

• White‑box test: The security team has full knowledge of the system (code, architecture, credentials). Ideal for deep, thorough testing.
• Black‑box test: The tester has no prior knowledge, simulating an external attacker.
• Grey‑box test: The tester has limited knowledge (e.g., low‑privilege credentials).

Testing focuses:

• External testing: Tests remotely visible entry points: servers, devices, web applications.
• Internal testing: Performed from behind the firewall by an authenticated user, simulating an insider threat or a compromised internal machine.

3. Security Risk Assessment

This involves appraising the risk of the security system by examining and analysing potential threats. Threats are then categorised into high, medium, and low based on severity level. Defining the right mitigation strategies based on the application’s security posture follows.

4. Ethical Hacking

Ethical hacking uses an authorised methodology to enter the system following the path of real hackers. The application is attacked from inside to uncover security defects and vulnerabilities, identifying potential hazards that malicious hackers may exploit.

5. Security Scanning

To enhance the scope of security testing, testers should conduct security scans to assess network weaknesses. Each scan sends malicious requests to the system. Testers must check for behaviour that could indicate a security weakness.

Common scan types:

• SQL Injection
• XPath Injection
• XML Bomb / Malformed XML
• Cross‑Site Scripting (XSS)
• Malicious Attachments
• Invalid Input Types

Vulnerabilities discovered during scanning are then analysed and fixed.

6. Access Control Testing

Access control testing ensures that the application can only be used by authorised, authentic users. The purpose is to survey the filtering approach of software components and ensure that the application’s execution aligns with security policies, guarding the system against unauthorised users.

For a deeper look at penetration testing, read Everything You Need to Know About Web Application Penetration Testing.

Information Security Testing in Agile and DevOps

In modern development environments, security cannot be a separate, final‑phase gate. Instead, security must be embedded into the CI/CD pipeline—a practice often called DevSecOps.

Key practices:

• Static Application Security Testing (SAST): Scan source code for vulnerabilities on every commit.
• Dynamic Application Security Testing (DAST): Scan running applications in staging environments.
• Software Composition Analysis (SCA): Scan third‑party libraries and dependencies for known vulnerabilities.
• Container scanning: Scan Docker images for vulnerabilities before deployment.
• Infrastructure as Code (IaC) scanning: Check Terraform, CloudFormation, or Kubernetes manifests for misconfigurations.

Automated security scans should run alongside unit and integration tests, failing builds if critical vulnerabilities are found.

For a deeper understanding of CI/CD security integration, read The Ideal DevOps Technique: Best Methods for Continuous Testing.

Best Practices for Information Security Testing

1. Shift Left – Start Early

Begin security testing during the requirements phase. Define security requirements and conduct threat modelling before writing code.

2. Automate Where Possible, But Don’t Neglect Manual Testing

Automation catches known vulnerability patterns quickly. Manual testing (ethical hacking) uncovers logic flaws, business logic abuses, and novel attack paths that automated scanners miss.

3. Use a Risk‑Based Approach

Not every vulnerability has the same impact. Prioritise fixes based on exploitability and business impact (CVSS scores). Focus on critical and high‑severity findings first.

4. Test in Production (Safely)

Use techniques like canary deployments, feature flags, and runtime application self‑protection (RASP) to monitor security in production without disrupting users.

5. Regularly Update Your Threat Model

As your application evolves, new features introduce new risks. Revisit threat modelling quarterly or after major feature releases.

6. Train Your Team

Security is everyone’s responsibility. Provide regular training on secure coding, OWASP Top 10, and emerging threats.

For a framework to measure your security testing effectiveness, read Essential Test Metrics and KPIs for Measuring QA Success.

Common Security Testing Pitfalls and How to Avoid Them

How TestUnity Helps with Information Security Testing

At TestUnity, we specialise in comprehensive information security testing services. Our experts can help you:

• Conduct vulnerability assessments using industry‑leading tools.
• Perform manual penetration testing (white‑box, black‑box, grey‑box) to uncover hidden vulnerabilities.
• Integrate security scanning (SAST, DAST, SCA) into your CI/CD pipeline for continuous security.
• Provide risk assessments and prioritised remediation guidance.
• Support compliance validation for GDPR, HIPAA, PCI DSS, and other regulations.
• Train your team on secure coding and security testing best practices.

Protect your data, your customers, and your reputation with TestUnity’s expert security testing services.

Conclusion

Information security testing is no longer optional—it is a business imperative. A single data breach can cost millions in fines, legal fees, and lost revenue, not to mention the long‑term damage to brand trust.

Key takeaways:

• Integrate security testing from the start – shift left.
• Combine automated scanning and manual penetration testing for comprehensive coverage.
• Use a risk‑based approach to prioritise fixes.
• Embed security into your CI/CD pipeline (DevSecOps).
• Regularly update threat models and retest after changes.

By adopting a proactive, continuous approach to information security testing, you can protect your organisation from evolving cyber threats and build trust with your customers.

Ready to secure your applications? Contact TestUnity today to discuss how our information security testing experts can help you build a robust defence.

Related Resources

• Everything You Need to Know About Web Application Penetration Testing – Read more
• Cyber Security Testing Checklist: 9 Essential Steps for Product Security – Read more
• API Security Testing: Rules, Checklist & 2026 Best Practices – Read more
• Why Outsource Cyber Security Testing? – Read more
• A Checklist Every Developer Must Have For Mobile App Security Testing – Read more
• 7 Tips for Developing the Ultimate Test Automation Strategy – Read more
• The Ideal DevOps Technique: Best Methods for Continuous Testing – Read more
• Essential Test Metrics and KPIs for Measuring QA Success – Read more

TestUnity

TestUnity is a leading software testing company dedicated to delivering exceptional quality assurance services to businesses worldwide. With a focus on innovation and excellence, we specialize in functional, automation, performance, and cybersecurity testing. Our expertise spans across industries, ensuring your applications are secure, reliable, and user-friendly. At TestUnity, we leverage the latest tools and methodologies, including AI-driven testing and accessibility compliance, to help you achieve seamless software delivery. Partner with us to stay ahead in the dynamic world of technology with tailored QA solutions.