This content originally appeared on DEV Community and was authored by Dhruv Joshi
Hey there.
If you’re reading this, chances are you’re a developer or someone who works closely with code. Maybe you’re building your own app, working on a team project, or just getting started in the dev world. Wherever you are in your journey, one thing is super clear: security matters. A lot.
But here’s the thing: most of us mess it up at some point. And usually, not on purpose. It’s often just because we’re moving fast, or we don’t realize something we’re doing is risky. I’ve been there. I’ve made these mistakes. Pretty much everyone has.
In this post, I want to walk you through five common security mistakes that developers often make. And more importantly, I’ll show you how to avoid them. No tech jargon. No over-complicated explanations. Just real talk.
Let’s jump in.
1. Hardcoding Secrets
Let’s start with one that almost every dev has done, especially when starting out. You’re testing out your app, and you need to connect to a database or an API. So what do you do? You drop your API key or database password right into your code. It works, right? Problem solved.
Until one day you push that code to GitHub.
Oops.
Now your secret key is out there for anyone to see. And bots scan GitHub all the time looking for this stuff. They’ll find it. And when they do, they’ll use it. Could be to send spam through your email provider. Could be to rack up charges on your cloud account. Either way, not fun.
How to avoid it
Use environment variables. Every programming language supports this in some way. Put your secrets in a .env file, then use a library like dotenv to load them in. And please, never commit your .env file. Add it to .gitignore.
Also, tools like GitHub Actions let you store secrets securely. Use those for deployment.
2. Not Validating User Input
Here’s another classic mistake. You have a form. Maybe it asks for a name or email. Or maybe it's a comment box. The user fills it in, hits submit, and it goes into your database.
But here’s the problem. What if the user doesn’t type their name? What if they type JavaScript code? Or SQL code? What happens then?
If you’re not careful, your site could be vulnerable to something called injection attacks — like SQL injection or cross-site scripting (XSS). These can be really bad. We’re talking stolen data, broken layouts, or even users getting hacked.
How to avoid it
Always validate and sanitize user input. Always.
If someone types in a number, make sure it's actually a number. If you expect an email, check that it's a valid email. Never just assume the input is safe.
Also, use libraries and frameworks that help you escape inputs properly. For example, use prepared statements when working with SQL. And use template engines that automatically escape HTML to avoid XSS.
3. Poor Password Handling
Passwords. We all deal with them. And honestly, it’s easy to mess this up.
Some developers still store passwords in plain text. Please don’t do that. Ever.
Others might hash passwords, but they use weak or outdated algorithms like MD5. Or they don’t use salts. Or they forget to rehash passwords when their algorithm changes.
All of this makes it way easier for someone to crack user accounts if your database gets leaked.
How to avoid it
Use a strong hashing algorithm like bcrypt or Argon2. These are designed for passwords. They’re slow by design, which makes them hard to brute-force.
Also, always salt your passwords. A salt is just a random string added to the password before it’s hashed. It makes it way harder for attackers to use precomputed tables.
And of course, don’t roll your own password system unless you really know what you’re doing. Use a trusted authentication library or framework that handles all this for you.
4. Giving Too Much Access
This one’s a little more subtle, but it’s just as dangerous. Let’s say your app has users. Some are admins. Some are regular users. Maybe some are guests. Do all of them have the same permissions?
If you’re not careful, a regular user might be able to access something they shouldn’t. Like your admin panel. Or someone else’s data.
This is called broken access control, and it’s one of the most common and dangerous security flaws out there.
How to avoid it
Use role-based access control (RBAC). That means you check what kind of user is making a request, and only let them do what they’re supposed to be allowed to do.
Always verify permissions on the server side. Never rely on the frontend alone to hide or show features.
For example, just because you don’t show the “delete” button in the UI doesn’t mean someone can’t send a delete request directly to your API. Your backend should still check whether that user is allowed to do that action.
5. Ignoring Security Updates
Let’s be honest. Most of us hate updates. Whether it’s our phone, laptop, or code dependencies, we tend to put off updates for as long as possible.
However, in the development world, ignoring updates can be a significant mistake.
Why? Because software libraries often have bugs. And some of those bugs are security vulnerabilities. When they get discovered, the people who maintain those libraries usually release a fix. But if you’re still using the old version, you’re exposed.
How to avoid it
Keep your dependencies up to date. Use tools like npm audit or pip-audit to check for known vulnerabilities in your packages.
Also, be cautious when using third-party libraries. Only use packages from trusted sources. And check how often they’re updated. If a package hasn’t been touched in years, that’s a red flag.
It may take some time to stay on top of updates. But it’s nothing compared to the mess you’ll deal with if someone exploits a known vulnerability in your app.
Final Thoughts
Security isn’t something you do once and forget about. It’s something you bake into your process from day one. It’s not just about writing code that works; it’s about writing code that’s safe.
The mistakes I talked about here are super common. I’ve made some of them myself. You probably have too. The key is learning from them and doing better next time.
So here’s a quick recap:
- Don’t hardcode secrets. Use environment variables.
- Validate and sanitize every bit of user input.
- Store passwords the right way with bcrypt or Argon2.
- Check your permissions on every request.
- Stay on top of updates and audits.
None of this is about being perfect. It’s about being responsible.
Your users trust you. They give you their data. Their time. Sometimes even their money. At the very least, we can protect that trust.
Thanks for reading. Stay safe out there.
This content originally appeared on DEV Community and was authored by Dhruv Joshi
Dhruv Joshi | Sciencx (2025-06-20T15:04:31+00:00) Top 5 Security Mistakes Devs Make (and How to Avoid Them). Retrieved from https://www.scien.cx/2025/06/20/top-5-security-mistakes-devs-make-and-how-to-avoid-them/
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