Building a secure app is essential in today’s world. Your users trust you with their data, and it’s your job to keep it safe. Whether you’re building a small app or a large-scale platform, security should always be a priority. In this post, we’ll cover common security mistakes and how to easily avoid them, so you can ensure that your app is production-ready and protected against attacks.
1. Ignoring CORS (Cross-Origin Resource Sharing)
The Mistake:
By leaving CORS open to all domains, anyone can make requests to your server. This opens the door for cross-site scripting (XSS) attacks.
The Risk:
Attackers can inject harmful scripts into your website, potentially stealing user data or spreading malware.
The Fix:
Always restrict CORS access to trusted domains, ensuring only your frontend app can interact with your backend.
2. Not Using Rate Limiting to Prevent DDoS Attacks
The Mistake:
Without rate limiting, your app is vulnerable to DDoS attacks (Distributed Denial-of-Service), where attackers overwhelm your server with requests.
The Risk:
Your app could go down, leaving users unable to access your service.
The Fix:
Limit the number of requests a user can make in a short period. This prevents abuse and helps keep your app running smoothly.
3. Storing Plain Text Passwords (Big No-No!)
The Mistake:
Storing plain-text passwords is a massive security risk. If your database is compromised, all your users’ passwords are exposed.
The Risk:
If attackers get hold of your database, they can see and misuse user passwords.
The Fix:
Hash passwords before storing them. This makes it impossible for anyone (even if they breach your database) to access your users’ actual passwords.
4. Allowing Unlimited Failed Login Attempts
The Mistake:
Without limiting failed login attempts, attackers can try as many passwords as they want, potentially gaining access to user accounts through brute-force attacks.
The Risk:
Hackers can easily guess passwords if you don’t limit login attempts, compromising user accounts.
The Fix:
Lock accounts temporarily after several failed login attempts to prevent brute-force attacks.
5. Skipping Email Verification
The Mistake:
Allowing users to log in without verifying their email could let attackers create fake accounts or take over legitimate ones.
The Risk:
Without email verification, unauthorized users could easily gain access to sensitive accounts.
The Fix:
Verify email addresses by sending an OTP (One-Time Password) to ensure the user’s email is valid before allowing them to log in.
6. Storing Sensitive Data Unencrypted
The Mistake:
Storing sensitive data like API keys or user information without encryption makes it easy for attackers to steal and misuse it.
The Risk:
If attackers breach your database, they can easily extract and use sensitive data.
The Fix:
Always encrypt sensitive data (like passwords, keys, and personal information) before storing it in your database.
7. Not Sanitizing User Input
The Mistake:
Allowing unsanitized user input could lead to SQL injection or NoSQL injection attacks, where malicious data is inserted into your database.
The Risk:
Attackers can manipulate your database queries, leading to data breaches or application malfunctions.
The Fix:
Sanitize user input to remove any harmful or unauthorized content before storing or processing it.
8. Skipping Authentication & Authorization
The Mistake:
If you allow users to access sensitive data without proper authentication or authorization, they could exploit your app to access things they shouldn’t.
The Risk:
Without proper checks, unauthorized users could view or manipulate private data.
The Fix:
Implement authentication to verify who users are and authorization to check what actions they can perform. Only allow users to access data they’re allowed to see.
9. Using Long-Expiry JWT Tokens Without Refresh Mechanism
The Mistake:
Using JWT (JSON Web Tokens) with long expiry times without a refresh mechanism can expose your app to security risks. If a token is compromised, the attacker could use it indefinitely.
The Risk:
If a token is stolen, an attacker can access the app until the token expires, which could be a long time if the expiry time is too long.
The Fix:
Use short expiry times for access tokens (e.g., 15–30 minutes) and implement refresh tokens to securely renew access when needed. This ensures that even if a token is compromised, it won’t be useful for long.
10. Not Using HTTPS for Secure Communication
The Mistake:
Using HTTP instead of HTTPS exposes your app to man-in-the-middle (MITM) attacks, where an attacker can intercept and alter data sent between your server and client.
The Risk:
Sensitive information, such as passwords and credit card details, could be intercepted and stolen by attackers.
The Fix:
Always use HTTPS to encrypt the communication between the client and server, ensuring that no one can tamper with your data.
11. Not Regularly Updating Dependencies
The Mistake:
Using outdated libraries and frameworks increases the risk of your app being vulnerable to known exploits.
The Risk:
Attackers can exploit vulnerabilities in outdated dependencies to compromise your app.
The Fix:
Regularly update your dependencies to ensure you’re using the latest, most secure versions. Use tools like Dependabot or npm audit to keep track of vulnerabilities in your dependencies.
12. Not Implementing Proper Logging and Monitoring
The Mistake:
Without logging and monitoring, it’s hard to detect suspicious activity or attacks.
The Risk:
If something goes wrong, you may not know until it’s too late. This could lead to data breaches or service downtime.
The Fix:
Implement logging and monitoring tools to track activities within your app. Tools like AWS CloudWatch or Prometheus help you detect unusual activity early.
Conclusion: Secure Your App, Secure Your Users! 
Security is non-negotiable when it comes to building apps. By avoiding these common mistakes and following these simple best practices, you’ll make sure that your app is both safe and production-ready. Here’s a quick recap of the key points:
Always use short expiry JWT tokens with refresh tokens.
Sanitize and validate user inputs.
Use HTTPS to secure communication.
Implement rate limiting to protect from DDoS attacks.
Regularly update your dependencies.
By focusing on security from day one, you’ll not only protect your users’ data but also build trust and ensure that your app is scalable and secure for the long run.
Ready to secure your app? Drop your thoughts and any questions below! Let’s keep building safe and secure apps together.
