Security Is a Developer Responsibility
Cybersecurity is no longer just the security team's problem. Modern development practices — from DevOps to cloud-native architectures — mean developers are often the first (and sometimes only) line of defense. Understanding the most common threats is a foundational skill for any serious developer.
1. SQL Injection (SQLi)
SQL injection remains one of the most prevalent and damaging vulnerabilities in web applications. It occurs when user-supplied input is embedded directly into SQL queries without sanitization, allowing attackers to manipulate database logic.
Example attack: An input field that accepts ' OR '1'='1 to bypass authentication.
Prevention: Always use parameterized queries or prepared statements. Never concatenate user input into SQL strings.
2. Cross-Site Scripting (XSS)
XSS attacks inject malicious scripts into web pages viewed by other users. When successful, attackers can steal session cookies, redirect users, or perform actions on their behalf.
- Stored XSS: Malicious script is saved in the database and served to all users.
- Reflected XSS: Script is embedded in a URL and executed when a victim clicks it.
- DOM-based XSS: Exploits client-side JavaScript that writes to the DOM unsafely.
Prevention: Encode all output, use Content Security Policy (CSP) headers, and sanitize HTML inputs with trusted libraries.
3. Broken Authentication
Weak or improperly implemented authentication systems are routinely exploited. Common issues include weak passwords, missing multi-factor authentication, insecure session token management, and credential stuffing vulnerabilities.
Prevention: Implement MFA, use secure session management, enforce strong password policies, and consider established auth libraries rather than rolling your own.
4. Insecure Direct Object References (IDOR)
IDOR vulnerabilities occur when an application exposes internal implementation objects (like database IDs) directly in URLs or parameters without proper authorization checks. An attacker changes /invoice?id=1001 to /invoice?id=1002 and accesses someone else's data.
Prevention: Always verify that the authenticated user has permission to access the requested resource — never trust client-supplied IDs alone.
5. Supply Chain Attacks
Modern applications depend on hundreds of third-party libraries and packages. Attackers have increasingly targeted this software supply chain by compromising popular open-source packages, inserting malicious code that gets distributed to thousands of downstream applications.
Prevention: Audit your dependencies regularly, use tools like Snyk, Dependabot, or npm audit, pin dependency versions, and monitor for unexpected updates.
6. Sensitive Data Exposure
Failing to properly protect sensitive data — passwords, credit card numbers, personal information — is a perennial vulnerability. Common failures include storing passwords in plaintext, using weak encryption algorithms, or transmitting data over HTTP.
Prevention: Hash passwords with bcrypt or Argon2, use TLS everywhere, encrypt sensitive data at rest, and avoid logging sensitive information.
Building a Security Mindset
The best defense is building security thinking into every stage of development:
- Threat model during design, not after deployment.
- Use the OWASP Top 10 as a regular reference checklist.
- Conduct code reviews with security in mind.
- Run automated security scanning in your CI/CD pipeline.
- Keep all dependencies and frameworks up to date.
Security isn't a feature you add at the end — it's a practice woven through every commit.