Essential Security Checklist for Web Apps: From Unit Tests to Encryption

Unit Testing

Repeated cycles of modify → test → modify → test can introduce hidden security flaws, especially when a change is reused across multiple modules. Using a testing framework to call functions with specific parameters and assert expected results helps ensure that functionality behaves correctly and prevents security incidents, such as an isAdmin() function unintentionally granting admin rights.

Access Control

Improper access control is a critical risk in custom‑built applications, allowing users to elevate privileges or access unauthorized resources. Strict access‑control checks must be enforced for any high‑privilege operation or content.

Change Tracking / Version Control

Tracking changes to code and configuration files is essential for reliability, auditability, and detecting tampering. Using source‑code management systems like Git or SVN records who changed what, when, and where.

Administrative Privileges

In larger teams, the number of users with admin‑level rights can grow, encompassing not only root access on servers but also write access to Git repositories and instance‑level cloud credentials. Audit logs help trace actions, but the primary goal is to ensure only appropriate personnel hold necessary privileges.

Least Privilege

Building on admin‑privilege management, always apply the principle of least privilege. When granting access, determine the minimal set of permissions required; a web app typically does not need full filesystem or database access.

Remote Redundancy

Effective logging often requires storing logs off‑site to prevent tampering. Remote backup and multi‑region redundancy improve stability, uptime, and disaster‑recovery capabilities.

Monitoring

Beyond redundancy, proactive monitoring can detect issues as they occur, enabling preventive actions before major failures. Good monitoring also reveals cascading effects, such as a single service outage propagating to dependent services.

Encryption

Many web applications still transmit credentials over non‑SSL connections or store passwords using weak hashes like MD5 or SHA‑1. Employ TLS certificates for transport security and use strong, salted hash algorithms (e.g., SHA‑512) for stored passwords to reduce unauthorized data access.

Web Security Scanners

Combining every feature and user action creates an exponential number of potential security states, making manual testing impractical. Automated web security scanners can both test for known vulnerabilities and uncover issues developers might overlook.

SQL Injection

SQL injection remains the top‑ranked OWASP risk. Prevent it by using prepared statements and properly sanitizing user input.

Conclusion

The list above is not exhaustive; a truly comprehensive checklist would span thousands of items and entire books. Security requires understanding edge cases and thinking beyond conventional patterns.