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8 Web Application Security Best Practices for 2024

8 Web Application Security Best Practices for 20248 Web Application Security Best Practices for 2024

Just one threat to your web application can bring your organization crashing down. The consequences for your legal department, IT teams, and customers create massive headaches, and it’s too easy to believe that an attack will not target your business. 

Yet, everyone is a potential target – a staggering 98% of web applications are vulnerable to cyber attacks like broken authentication and misconfigurations, making web application security best practices an absolute priority. 

What is Web Application Security?

Web application security is the process of protecting APIs, websites, applications, and other online services from various threats, including unauthorized access and data breaches.

The process of web application security involves three main steps: 

  • Identifying: Finding potential security weaknesses in web applications before attackers can exploit them. Security audits, code reviews, and error monitoring are widely used identification methods.

  • Fixing: Addressing and resolving the vulnerabilities found during the identification phase. Patching vulnerabilities, security updates, and code improvements are common techniques used for this purpose.

  • Preventing: Implementing measures and practices that reduce the risk of future security breaches. Techniques like input validation, encryption, access control, and training are used for prevention.

Everyone involved in the software development life cycle (SDLC) needs web application security, from developers to organization managers and even end users interacting with these services.

As the internet becomes increasingly integral to daily life, ensuring the safety and integrity of applications is crucial for protecting sensitive data and maintaining trust between users and service providers.

Why Should You Care About Web Application Security?

The main benefits of prioritizing web application security include:

  • Protects Sensitive Data: Prioritizing security helps protect sensitive data from unauthorized access, which could lead to financial loss, identity theft, and reputation damage.

  • Maintains Customer Trust and Brand Integrity: A single security breach can significantly harm your organization's reputation. Hence, implementing strong web application security measures demonstrates to your customers that you value their privacy and are committed to protecting their data.

  • Reduces Risk of Financial Loss: Helps avoid losses from cyber attacks like theft, account take over, ransomware payments, and fraud. Additionally, the aftermath of a breach can be costly, involving legal fees, fines, and expenses related to remediation.

10 Web Application Security Best Practices for 2024

Creating a secure web application environment is more challenging than it sounds. Let's consider ten web application security best practices for 2024.

1. Input Validation

open-appsec login win

Input validation is a coding best practice that ensures only properly formatted data enters a workflow in a web application. It involves checking every user input against rules that define what is acceptable and what is not. Without input validation, attackers can inject malicious data that could exploit vulnerabilities in the web application through attacks like SQL injection, cross-site scripting (XSS), and command injection.

Actionable Tips

  • Define Allowed Data: Clearly define the data type (specific data formats, types, ranges, or sets of acceptable values) allowed for each input field.

  • Use Built-In Features: Many frameworks and libraries have built-in validation features. For example, the below code shows how to use HTML5's built-in input types for basic client-side validation to validate emails.

<input type="email" name="email" required>

  • Validate on the Server Side: Always perform validation on the server side, even if you do it on the client side, since attackers can easily bypass client-side validation. The below example shows how to validate an email address on the server side with Python.

from flask import request
import re
@app.route('/register', methods=['POST'])
def register():
    email = request.form['email']
    if not re.match(r"[^@]+@[^@]+\.[^@]+", email):
        return "Invalid email address.", 400# Process the valid email

  • Regular Expression (Regex) Checks: Use regular expressions to validate inputs that should follow a specific format, such as email addresses, phone numbers, or usernames.

  • Test Validations: Use unit and integration tests to test input validation logic.

2. Parameterized Queries

Parameterized queries are a method of executing SQL queries in which user inputs are passed as parameters, separated from the SQL query itself. This technique makes the database treat input data as data only, not executable code, effectively neutralizing the threat of SQL injection attacks.

Here is an example of using parameterized queries with Python and SQLite.

import sqlite3
# Connect to SQLite database
connection = sqlite3.connect('example.db')
cursor = connection.cursor()
# Safe parameterized query
user_id = 'example_user_id'
cursor.execute("SELECT * FROM users WHERE id = ?", (user_id,))

Actionable Tips:

  • Use ORM Libraries: Object-relational mapping (ORM) libraries often abstract SQL operations and use parameterized queries or similar safe methods to interact with the database.

  • Code Review and Auditing: Review database access code regularly to ensure that parameterized queries are used consistently throughout the application. 

3. Encryption

Funny meme about encryption quoting the different terms it's referred to

Encryption converts plain text or data into a coded format (ciphertext) that is unreadable without the decryption key. It's a fundamental security practice for protecting data at rest and in transit. This process ensures user privacy, secures financial transactions, and helps comply with data protection regulations.

Actionable Tips:

  • Implement SSL/TLS for Data in Transit: Use HTTPS to encrypt data transmitted between the client and server. You can configure your web server to use SSL/TLS certificates. 

  • Encrypt Sensitive Data at Rest: Use strong encryption standards like AES (Advanced Encryption Standard) to encrypt stored data. Here is an example of using AES with Python:

from Crypto.Cipher import AES
import os
key = os.urandom(16)  # Generate a secure random key
cipher =, AES.MODE_CFB)
msg = cipher.encrypt(b'Sensitive data')
print(msg)  # Encrypted data

  • Key Management: Use dedicated hardware security modules (HSMs) or key management services provided by cloud providers (AWS KMS) to store and manage encryption keys.

AWS KMF Workflow

4. Least Privilege

The principle of least privilege states that users should only be granted the minimum permissions required to perform their duties. This practice helps limit the potential impact of security breaches. For example, if a user with excessive permissions is compromised, the attacker can exploit those privileges to cause significant harm. By enforcing the least privilege, you can drastically reduce the attack surface.

Actionable Tips:

  • Implement Role-Based Access Control (RBAC): Define roles within your application based on job functions and assign permissions to these roles rather than individual users. For example, an application might have roles like 'Administrator,' 'Editor,' and 'Viewer,' with different permission levels.

  • Use Access Control Lists (ACLs): ACLs can fine-tune access to specific resources. For example, you can configure ACLs on a file server to ensure that only members of the HR department can access employee data files.

  • Automate Provisioning and Deprovisioning: Automate the process of granting and revoking access to user roles when users join and leave to reduce the chance of human errors. 

5. Use HTTPS

HTTPS ensures secure communication over a computer network by encrypting data exchanged between the client and server. It utilizes SSL/TLS protocols to provide encryption and authentication, ensuring that data cannot be intercepted or tampered with during transit. HTTPS protects your data against eavesdropping, man-in-the-middle (MITM), and content tampering attacks.

Actionable Tips:

  • Obtain an SSL/TLS Certificate: Certificates can be acquired from a Certificate Authority (CA) like Let's Encrypt.

Let's Encrypt Website

  • Enforce HTTPS: Use HTTP Strict Transport Security (HSTS) header to inform browsers to only connect to your website using HTTPS. This prevents downgrade attacks.

Header always set Strict-Transport-Security "max-age=31536000; includeSubDomains"

  • Test HTTPS Configuration: Use tools like SSL Labs' SSL Test to analyze SSL/TLS configuration and identify potential vulnerabilities.

6. Session Management

Session management allows web applications to maintain state and track user activities across multiple requests. It creates a unique session for each user while interacting with the application. Secure session management is crucial for preventing hijacking, fixation, and replay attacks.

Actionable Tips:

  • Use Secure, Random Session Identifiers: Generate session IDs using a secure, cryptographically strong random number generator. Here is how to generate unique identifiers with Node.js using crypto:

const crypto = require('crypto');
function generateSessionId() {
  return crypto.randomBytes(16).toString('hex');

  • Set Secure Cookie Attributes: Mark session cookies as Secure and HttpOnly to protect them from being accessed by client-side scripts. Example for setting cookies in Node.js:

app.get('/set-cookie', (req, res) => {
    res.cookie('sessionID', 'yourRandomSessionId', {
        secure: true,  
        httpOnly: true,  
        sameSite: 'strict', 
        domain: '',
        path: '/',
        expires: new Date(0)
    res.send('Cookie has been set');
app.listen(port, () => {

  • Implement Session Expiration and Logout: Automatically expire sessions after a period of inactivity and immediately destroy sessions on logout.

  • Validate Sessions on Each Request: Check each request's session ID and user-associated details like IP address or user-agent string.

7. Regular Security Audits

As web applications evolve with new features and updates, new security vulnerabilities can be introduced. Regular security audits help identify and mitigate these new vulnerabilities before they can be exploited. Furthermore, they are critical for maintaining compliance with security standards and regulations.

Actionable Tips:

  • Conduct Vulnerability Assessments and Penetration Testing: Use automated tools to scan your web application for known vulnerabilities, such as SQL injection, XSS, and misconfigurations. Use SpectralOps for scanning and Metasploit manual testing techniques for penetration testing.

OWASP ZAP Dashboard

  • Audit Code for Security Flaws: Utilize Static Application Security Testing (SAST) tools like SonarQube and Checkmarx to automatically detect security issues in the codebase.

  • Training and Awareness Programs: Regularly train employees on the latest cybersecurity threats and safe practices. Conduct phishing simulation exercises to prepare employees for real-world attacks.

8. Use a Web Application Firewall (WAF)

A Web Application Firewall (WAF) is a security solution designed to monitor, filter, and block potentially harmful HTTP traffic to and from a web application. It acts as a gatekeeper between the application and the Internet, deciding which traffic is safe and which is not based on a set of defined rules.

Actionable Tips:

  • ML and AI: Select a WAF tool like open-appsec that supports machine learning (ML) and artificial intelligence (AI) to improve threat detection over time and reduce false positives. 

  • Evaluate Threat Support: WAF tools help you protect applications against various threats, including SQL injections, XSS, the OWASP Top 10, and more. For example, open-appsec even extends to support against zero-day threats and other yet-unknown attacks, such as Log4Shell. 

View of open-appsec WAF Website

  • Customize WAF Policies: First, set the WAF to a learning mode to understand typical traffic patterns and accurately configure rules. Then, customize WAF policies to address the specific security risks of your application.


open-appsec is an open-source project that builds on machine learning to provide pre-emptive web app & API threat protection against OWASP-Top-10 and zero-day attacks. It simplifies maintenance as there is no threat signature upkeep and exception handling, like common in many WAF solutions.

To learn more about how open-appsec works, see this White Paper and the in-depth Video Tutorial. You can also experiment with deployment in the free Playground.


Experiment with open-appsec for Linux, Kubernetes or Kong using a free virtual lab

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