Web Application Security Testing: A Practical Guide for Product Teams

Web applications are among the most common targets for attackers. Security testing finds weaknesses before they do — but only if it is done continuously, not once before launch.

Know the common risks

The OWASP Top 10 is the standard starting point. Key risks include:

• Broken access control — users reaching data or actions they should not
• Injection — SQL, command and other injection flaws
• Authentication failures — weak login, session and password handling
• Security misconfiguration — default settings, verbose errors, open storage
• Vulnerable components — outdated libraries with known flaws
• Server-side request forgery and insecure design choices

Layers of testing

Static analysis (SAST)

Scans source code for risky patterns on every pull request.

Dependency scanning

Flags libraries with known vulnerabilities and suggests updates.

Dynamic testing (DAST)

Tests the running application from the outside, like an attacker would.

Manual security review

Experienced testers examine business logic, access control and workflows that automated tools miss — such as whether one customer can view another's invoice by changing an ID.

Penetration testing

Independent experts attempt to break in, usually before major launches and periodically after.

Build it into delivery

1. Threat model new features during design
2. Run automated scans in CI
3. Review security-sensitive changes carefully
4. Fix high-severity issues before release
5. Re-test after fixes

Do not forget APIs

Mobile apps and single-page applications rely on APIs. Test authorisation on every endpoint, rate limits and input validation.

Compliance

PCI DSS, SOC 2, ISO 27001, HIPAA and regional regulators often require evidence of regular testing.

See our testing and QA and application security services.