The Web App Security Checklist: 10 Best Practices to Protect Your Website
Team Fueler

29 Aug, 2023

The Web App Security Checklist: 10 Best Practices to Protect Your Website

You’ve spent months building your web application and it’s finally ready to launch. You’ve tested all the features and worked out all the bugs. Your app looks great and functions perfectly.

But have you thought about web app security? If not, your site could be vulnerable to attacks that compromise user data, steal credit card numbers, or completely take your site offline.

Web app security should be a top priority, not an afterthought. This article outlines 10 best practices you need to implement now to lock down your web app and protect your users.

Why You Should Care About Web App Security

As a website owner, you need to make web app security a top priority. Why? Because your site contains valuable data and resources that cybercriminals want to get their hands on. If they succeed, it could cost you big time.

  1. First, customer data like names, emails, addresses, and payment info are prime targets. If hacked, cybercriminals can steal identities, make fraudulent purchases, or sell the data on the dark web. You could face legal consequences and lose customer trust.
  2. Second, your website itself contains intellectual property and proprietary code that you don’t want stolen or manipulated. If hackers gain access, they could deface your site, hold it for ransom, or use vulnerabilities to attack your users.
  3. Third, inadequate security leaves you open to distributed denial of service (DDoS) attacks that flood your site with traffic and take it offline. This results in lost revenue, productivity, and reputation.

The bottom line is that web app security should not be taken lightly. Implementing best practices like strong passwords, two-factor authentication, regular updates, and penetration testing can help safeguard your site. If you experience an attack, having a response plan in place allows you to take swift action, minimize damage, and restore operations as quickly as possible.

Make web app security a priority today. The threats are real, but with vigilance and the proper safeguards in place, you can protect your site, customers, and business. The risks of doing nothing are simply too great.

Common Web Application Vulnerabilities

As a website owner, you need to be aware of the common vulnerabilities that put your web app at risk. The more you know, the better prepared you’ll be to protect your site and users.

  • Injection attacks: This is when malicious data is inputted into your site, like SQL injections that target your database. Always sanitize and validate user input to prevent this.
  • Broken authentication: If your login system has flaws, accounts can be compromised. Enforce strong passwords, limit login attempts, and use two-factor authentication when possible.
  • Sensitive data exposure: Make sure any private info like credit cards or social security numbers are encrypted and only accessed by authorized users. Don’t store sensitive data unless absolutely necessary.
  • Cross-site scripting (XSS): This is when attackers inject client-side scripts into your web pages. Properly encode or escape all user input that is displayed on web pages to thwart XSS attempts.
  • Broken access control: Restrict users to only accessing data and site sections they are authorized to view. Never trust user input for access control decisions.
  • Security misconfiguration: Double-check that all default configurations on your servers, databases, frameworks, and apps are secure. Stay on top of the latest security patches and updates to fix vulnerabilities.
  • Cross-site request forgery (CSRF): This tricks users into unknowingly submitting a malicious request to your website. Use CSRF tokens, same-site cookies, and CORS headers to prevent this.
  • Using components with known vulnerabilities: Keep all libraries, frameworks, and third-party code up to date to avoid exploit. Monitor regularly for new vulnerability disclosures.
  • Unvalidated redirects and forwards: Don’t redirect users to untrusted websites or allow arbitrary forwarding. Always validate the destination path or URL.
  • Insufficient logging and monitoring: Monitor your web app closely for suspicious activity and unauthorized access. Review logs regularly to quickly detect and respond to security incidents.

Staying on top of these common web vulnerabilities and taking the recommended precautions will help ensure your website is secure and your users’ data stays protected.

SQL Injection: What Is It and How to Prevent It

What Is SQL Injection?

SQL injection is a malicious attack where hackers enter SQL code into web forms to manipulate the database.

They trick the website into running SQL queries that it didn’t intend to run. This can have devastating consequences like stealing data, deleting records, or modifying data.

As a website owner, SQL injection is something you need to be aware of and take precautions against. The good news is, with some basic security practices, you can eliminate the risk of SQL injection attacks on your site.

How Does SQL Injection Work?

SQL injection works by exploiting vulnerabilities in SQL databases that are accessed by web applications. Hackers enter malicious SQL code into web forms, like login pages or search boxes. If the web app runs that code, the hacker can gain access to the database.

For example, say you have a login form with fields for username and password. A hacker could enter:

Username: 'OR 1=1; --

Password: anything

The code 'OR 1=1 will always be true, so the hacker will log in as the first user in the database. The – denotes a comment, ignoring the rest of the query.

How to Prevent SQL Injection

The main way to prevent SQL injection is through input validation and escaping. This means:

  • Validate all user input before using it in SQL queries. Check that the data entered matches the expected type (integer, string) and length.
  • Escape all user input before using it in SQL queries. This converts characters that could manipulate SQL into safe strings.
  • Use prepared statements instead of string concatenation. Prepared statements separate SQL from user input, preventing injected code from affecting the query.
  • Restrict database permissions so users only have access to the data they need.
  • Keep your web application and database software up to date with the latest patches. Updates often contain security fixes.

By making security a priority in your web app development, you can build a robust defense against SQL injection and other threats. Protecting your users’ data and privacy should be a top concern, so take the time to get it right.

Cross-Site Scripting (XSS): How to Protect Your App

Cross-site scripting, or XSS, is one of the most common web app vulnerabilities. It allows attackers to inject malicious code into your website, which can then be executed by users. As a website owner, you need to make sure you’ve secured your app against XSS. Here are some of the best practices to follow:

1. Validate and Escape All User Input

Any user input on forms, URLs, etc. should be validated and escaped before displaying it on your website. This includes data from third-party sources as well. Escape special characters like <, >, ", ', etc. to prevent the injection of HTML and JavaScript.

2. Use CSP (Content Security Policy)

A CSP allows you to control resources like JavaScript, CSS, images, etc. that your web app is allowed to load and execute. It can help prevent XSS since inline JavaScript cannot be executed. You define whitelist sources for different content types in the HTTP header.

3. Don’t Rely on Client-Side Validation Alone

While client-side validation using JavaScript is convenient, it can be bypassed. Always validate on the server-side as well before processing user input.

4. Be Cautious of DOM XSS

The DOM (Document Object Model) can also be a target for XSS. When using JavaScript to manipulate the DOM, be careful to escape untrusted data before inserting it.

5. Keep Frameworks and Libraries Up to Date

Vulnerabilities are often found in web frameworks, CMSs, and JavaScript libraries. Keep them up to date with the latest patches to ensure your app has the latest security fixes.

6. Conduct Penetration Tests

Hire a penetration testing service to try and hack into your web app. They can identify vulnerabilities you may have missed and help strengthen your security.

7. Monitor for XSS Attempts

Use a web app firewall or monitoring service to detect XSS attempts in real-time. React quickly to prevent exploitation and remediate the vulnerability.

Staying on top of XSS risks and following security best practices will help ensure your users’ data and privacy are protected.

Broken Authentication: Don’t Let Users Impersonate Other Users

Broken authentication allows attackers to access your web app by impersonating other users. This can enable them to access sensitive data or perform unauthorized actions. To prevent broken authentication, you need to properly implement authentication and session management in your web app.

1. Use Strong Passwords and Two-Factor Authentication

Require users to choose strong, unique passwords to access your web app. Also, enable two-factor authentication (2FA) whenever possible. 2FA adds an extra layer of security by requiring not just a password but also another piece of information like a security code sent to the user’s phone.

2. Properly Manage User Sessions

A user session refers to the period of time between when a user logs in and logs out of your web app. You need to properly manage these sessions to prevent attackers from hijacking them. Some key steps:

  • Generate long, random session IDs. Don’t use sequential IDs or embed any personal info in them.
  • Set session timeout periods. Sessions should timeout after a period of inactivity, like 30 minutes. This limits how long an attacker has to access a hijacked session.
  • Rotate session IDs on login and logout. Issue a new session ID whenever a user logs in or out. This invalidates any previously issued session IDs.
  • Use the “Secure” flag for session cookies. The Secure flag tells browsers to only send the cookie over HTTPS. This prevents attackers from accessing session IDs over unencrypted HTTP.
  • Store session data on the server, not the client. Don’t store user sessions in local or client-side storage. Store them on the server where they are less accessible to attackers.
  • Terminate all active sessions on password reset. When a user resets their password, terminate any existing sessions for that account. An attacker could be logged in with a hijacked session, so terminating all sessions logs them out.

3. Be Cautious of Cross-Site Request Forgery (CSRF) Attacks

CSRF attacks involve attackers tricking authenticated users into making unauthorized requests to your web app. To prevent CSRF, you should:

  • Use CSRF tokens for all state-changing requests (logouts, payments, etc.). A CSRF token is a random value supplied with each request that attackers cannot guess or reuse.
  • Check the HTTP Referer header. The Referer header indicates the page that loaded the request. For CSRF-sensitive operations, check that the Referer is from your own domain.
  • Use the “SameSite” attribute for session cookies. Setting this to “Strict” or “Lax” prevents the browser from sending session cookies on cross-site requests, blocking CSRF attacks.
  • Require POST requests for sensitive actions. Requiring the POST method, versus GET, makes C- SRF attacks more difficult.

Sensitive Data Exposure: Keep Users’ Information Safe

Keep Sensitive Data Secure

When building a web app, you collect and store information from your users. This data is a huge responsibility and needs to be properly secured. If hackers gain access, users’ sensitive details could be compromised.

As an app owner, you must safeguard users’ personal information. Personally identifiable information (PII) like names, passwords, credit card numbers, and social security numbers require the highest level of protection. If exposed, this data could be used for identity theft or other malicious purposes.

  • Use strong encryption like SSL/TLS to secure all sensitive data, especially when transmitting information over the internet. This helps prevent man-in-the-middle attacks where hackers eavesdrop on communications.
  • Store PII separately from the rest of your data. This limits how much is exposed if there is a breach. Use encryption here as well for an added layer of protection.
  • Require strong, unique passwords that contain a minimum of 8 characters including uppercase and lowercase letters, numbers and symbols. Enforce password expiry policies to prompt users to change them regularly.
  • Use two-factor authentication (2FA) which requires not only a password but also an SMS text message or authentication app to log in. This makes it much harder for hackers to access accounts.
  • Conduct regular penetration testing to identify vulnerabilities before hackers do. Then, patch any issues immediately.
  • Provide privacy policies that clearly disclose how users’ data is collected and used. Let people know their options for reviewing and deleting information. AdFixus also recommends using first-party data instead of third party ones since they provide more security.
  • Stay up-to-date with compliance regulations like the GDPR (General Data Protection Regulation) to properly handle users’ data. Failure to do so can result in major legal penalties.

Following these best practices will help ensure your users’ sensitive details remain private and secure. Make data protection a priority in your web app.

Broken Access Control: Restrict Access to Authorized Users Only

As a web app owner, one of your top priorities should be controlling who can access what data and features in your system. If just anyone can view, edit, or delete sensitive information, you’ve got a serious security vulnerability on your hands.

To avoid broken access control issues, you need to verify users and their permissions at every point of interaction. This means:

  • Assigning unique login credentials (username and password) to each user. Don’t have a single shared login across your team or organization.
  • Defining different user roles like admin, moderator, and subscriber. Admins may have full access, mods can edit content, subs can only view, etc.
  • Setting permissions for each role that specify exactly what they can do. For example, admins can add, edit and delete posts, mods can only edit and delete, subs have read-only access.
  • Double-checking a user’s role and permissions every time they try to do something on your site like view a page, edit content, delete a comment, etc. Don’t assume that just because a user is logged in that they have authorization for all features.
  • Logging out inactive users after a period of time. Don’t leave user sessions open indefinitely which could allow someone else to access the account if the user walks away from the computer.
  • Providing an “audit trail” that logs key events like login attempts, content changes, deletions, etc. This helps you monitor for suspicious activity and unauthorized access.
  • Testing and patching your web app regularly to fix any newly discovered vulnerabilities. Access control issues are often caused by software bugs, so staying up-to-date with the latest security updates is key.

Following these best practices will help ensure that your users and their data stay protected. Only authorized individuals will have access to the appropriate information and features. And you’ll have monitoring and controls in place to detect any unauthorized access attempts as quickly as possible.

Cross-Site Request Forgery (CSRF): How to Defend Against It

1. How do CSRF Attacks work?

A CSRF (Cross-Site Request Forgery) attack tricks your users into making unwanted requests on your website. It happens when a malicious site fools your users’ browsers into sending forged requests to your web app. Since the requests come from authenticated users, your app trusts them.

Yikes! That means hackers can do things like change account details, make purchases, or access sensitive data—all without your users knowing. Not good.

2. How to Defend Against CSRF?

The good news is CSRF attacks are preventable. Here are a few ways to defend your web app:

  • Use CSRF tokens: When a user logs in, generate a random token and store it in their session. Require that token with all state-changing requests. Since the hacker’s site won’t have that token, their forged requests will be rejected.
  • Use the SameSite cookie attribute: This tells browsers to only send certain cookies with requests from your own domain. So if a CSRF request comes from another site, the user’s login cookies won’t be attached—and the request will fail.
  • Require confirmation for sensitive actions: Don’t just let users change account settings with one click. Prompt them to confirm the action to make sure it’s legitimate. Hackers can’t confirm actions on a user’s behalf.
  • Use CAPTCHAs: Adding a CAPTCHA to sensitive forms or actions helps ensure that requests are coming from real users, not automated CSRF attacks.
  • Restrict requests to your domain: Use the CORS (Cross-Origin Resource Sharing) header to only allow state-changing requests from your own domain. This stops CSRF requests from other sites dead in their tracks.

By putting multiple defenses in place, you can securely protect your web app and users from CSRF attacks. Staying on top of web security best practices will give you peace of mind that your app is as protected as possible from outside threats. Implement these tips today to CRSF-proof your website!

Implement Logging and Monitoring

As a web app owner, you need to keep an eye on what’s happening with your site. Comprehensive logging and monitoring are key to detecting potential security issues quickly. Think of logging as your website’s diary—it records information about page views, logins, data access, and more.

Review your logs regularly for any weird or suspicious activity. Things like:

  • Multiple failed login attempts from the same IP address. This could indicate a brute force attack.
  • Access to admin areas from an unknown device or location. Your account may have been compromised.
  • SQL injection attempts in URL parameters or form fields. Hackers could be trying to access your database.

Set up alerts to notify you automatically when these types of events occur. Some logging services like Splunk, Datadog, and Papertrail offer built-in alerting features. You can also use a monitoring service like Pingdom or New Relic to keep tabs on your web app’s availability and performance.

Real-time alerts allow you to respond quickly to security incidents. The faster you can detect and remediate issues, the less damage will be done.

Regular log reviews and monitoring are two of the most important things you can do to protect your web app. Make time for them and take any notifications seriously. Your site’s security depends on it.

Don’t have time to dig through logs yourself? Outsource this task to a managed security services provider. They have the expertise to monitor your logs and alerts 24/7 and will notify you right away if they discover something suspicious.

Logging and monitoring: not the most glamorous part of running a web app, but absolutely critical for security. Make them a priority and encourage your whole team to get on board with a proactive approach to security monitoring.

FAQ: Answers to Common Questions About Web Application Security

What is SQL injection and how can I prevent it?

SQL injection is one of the most common web app security risks. It happens when a hacker enters malicious code into a web form to gain access to your database. To prevent SQL injection, always validate and sanitize user input before using it in SQL queries.

For example, if a user enters ‘ or 1=1; – in a login form, it could delete your entire database! Validate that users only enter expected input like letters, numbers, and a few symbols.

1. Why is cross-site scripting (XSS) dangerous and how do I avoid it?

XSS allows hackers to run malicious JavaScript code on your website. It happens when you display unsanitized user input on a page. To prevent XSS, always sanitize user input before displaying it.

For example, if a user enters in a comment form, it could pop up an alert for all your visitors! Sanitize input by replacing < and > with < and >.

2. What is a DDoS attack and how can I protect my site?

A DDoS or distributed denial-of-service attack floods your website with traffic to overwhelm your server and take the site offline. To prevent DDoS attacks, use a content delivery network (CDN) and DDoS mitigation service.

A CDN distributes your site content globally so no single server bears the brunt of the attack.

DDoS mitigation services filter out malicious traffic before it reaches your server. These services aren’t foolproof but can help minimize the impact of an attack.

3. Why is HTTPS important and how do I implement it?

HTTPS encrypts connections between your website and visitors to prevent eavesdropping. It’s important because without HTTPS, hackers can see your users’ passwords, credit cards, and other sensitive data. To implement HTTPS, you need an SSL/TLS certificate.

Once you install the cert on your server, all requests to your site will be encrypted. Many hosting providers offer free SSL certificates - use them!

Encrypting your site is one of the best things you can do for web security.


So there you have it, the 10 best practices to keep your web app secure and protected. Implementing these checks and security measures may require some time and resources, but it’s well worth the investment to avoid data breaches, hacked accounts, and damaged reputations.

Your users trust you with their information, and it’s your responsibility to safeguard it properly.

Stay on top of the latest web security threats and vulnerabilities, and keep testing and improving your web app defenses. The threats are real, but with the right checklist, you’ll be well prepared to face them.

Happy Coding!

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