Web Application Security and GDPR: What Every Business Must Know in 2025

Security Isn't Optional — It's a Requirement

In 2024, Europe recorded 1,200+ significant data breaches with total GDPR fines exceeding €2 billion. Web application security is no longer just the IT department's responsibility — it's a business risk.

Devs.lv has been conducting security audits and GDPR compliance assessments for 8+ years. In this article, we share a practical guide any business can implement.

OWASP Top 10 — Most Common Threats

1. Injection (SQL, XSS, LDAP)

Still the #1 vulnerability worldwide. The solution is simple but requires discipline:

Parameterized queries — never use string concatenation in SQL queries
ORM usage — Prisma, TypeORM, Sequelize automatically protect against SQL injection
Content Security Policy — CSP headers block XSS attacks even if code is vulnerable
Input validation — validate ALL input data on the server (not just client-side)

2. Authentication Failures

Weak passwords, no MFA, session management issues — the classics:

MFA mandatory — at minimum for admin users, ideally for everyone
Password policy — minimum 12 characters, checking against haveibeenpwned database
Session limits — automatic session expiry after inactivity, secure cookies (HttpOnly, Secure, SameSite)
Rate limiting — block brute-force attempts (max 5 tries, then lockout)

3. Sensitive Data Exposure

API responses returning more data than needed. Logs with personal data. Unencrypted databases.

API response filtering — return only necessary fields (not the entire database row)
Encryption — TLS 1.3 for transport, AES-256 for sensitive data at rest
Log sanitization — never log passwords, API keys, personal identification numbers

GDPR Compliance — Practical Steps

Consent Management

Every web application needs:

Cookie banner with granular consent (not just "Accept all")
Consent Mode v2 — Google requirement since March 2024. Affects GA4, Google Ads
Consent log — record when and what the user consented to. Authorities may request proof.

Data Processing Register

GDPR Article 30 requires documenting:

What personal data you collect and why
Where data is stored (EU or outside EU)
How long you retain data
Who has access

Right to Erasure

Users have the right to request deletion of their data. Your system must be able to:

Identify all user data across all systems (database, logs, backups, third-party services)
Delete or anonymize data within 30 days
Confirm deletion to the user

Security Headers — Quick Win

These HTTP headers protect against the most common attack vectors. Implementation takes 30 minutes:

Content-Security-Policy — blocks XSS and data injection
Strict-Transport-Security — enforces HTTPS (HSTS)
X-Frame-Options: DENY — protects against clickjacking
X-Content-Type-Options: nosniff — prevents MIME type sniffing
Referrer-Policy: strict-origin-when-cross-origin — limits referrer information
Permissions-Policy — blocks unnecessary browser APIs (camera, microphone, geolocation)

Devs.lv example: in our Next.js projects, all these headers are set at the middleware level, automatically applied to every request.

Regular Security Audits

Security isn't a one-time action. Recommended cycle:

Weekly: automated dependency scanning (npm audit, Snyk, Dependabot)
Monthly: OWASP ZAP or Burp Suite scanning
Quarterly: manual penetration test (internal or external)
Annually: full security audit with GDPR compliance check

Incident Response Plan

GDPR requires notifying authorities about data breaches within 72 hours. You must be prepared:

Contact person — who calls the authority and customers?
Investigation process — how do you identify the breach scope?
Communication plan — prepared templates for customers and press
Technical response — how do you isolate and fix the issue?

Conclusion

Web security and GDPR compliance aren't complicated — they require a systematic approach and regular maintenance. Start with security headers and OWASP Top 10, then move to GDPR documentation and regular audits.

Need a security audit? Devs.lv offers web application security audits that include OWASP testing, GDPR compliance assessment, and a concrete recommendation plan. Results within 5 business days.