15 Web Application Security Best Practices

Every day that an application is anything less than ‘fully secure’ is a day for a potential data breach.

Consumer data, sensitive business information, monetary transactions, and business reputation; everything is at stake.

Investing in effective web application security is the best and only way to mitigate the risk of financial losses and reputational damage for businesses.

This blog presents a comprehensive blueprint for implementing best practices for application security.

What is Web Application Security?

Web application security refers to the practices, tools, and measures implemented to protect web applications from various security threats and vulnerabilities. This includes safeguarding against unauthorized access, data breaches, injection attacks (such as SQL injection or cross-site scripting), and other malicious activities.

There are unknown vulnerabilities about which businesses and developers learn only when the breach has happened, called zero-day threats. Zero-day threats are the most dangerous owing to this very nature.

15 Best Practices for Web Application Security

1. Create a Web Application Threat Model

In today’s fast-paced business landscape, meeting customer demands often takes precedence over organized processes. With new applications, customer portals, and marketing integrations rolling out rapidly, it’s easy for businesses to lose track of their digital assets.

Without a clear understanding of the number of applications in use, their purpose, and their update status, implementing effective web application security becomes challenging. Therefore, it’s essential to address this issue as a priority.

To lay the foundation for a robust web application security model, start by creating a comprehensive database of all applications, akin to an inventory sheet. Include details such as the number of applications, their intended use, the last updated version, and any future plans for their utilization.

Additionally, document deployment modes, application layers, and existing security measures employed within each application. This holistic approach ensures that all assets are accounted for and enables quick and efficient vulnerability patching when necessary.

By establishing this baseline understanding of your application landscape, you pave the way for a more structured and effective web application security strategy.

2. Sort the Applications in Priority Buckets

With numerous applications to manage, it’s easy to lose focus on security priorities. Begin by defining priorities immediately after or during the app inventory process. Sort applications into Critical, Serious, and Normal categories to guide progress in the coming months.

• Critical: External-facing apps dealing with sensitive customer data and monetary transactions belong here. These apps are prime targets for hackers and should be tested and fixed as a priority.
• Serious: Both external and internal apps containing sensitive company and customer information fall into this category. They should be addressed promptly after critical apps.
• Normal: While hackers may not target these apps directly, they should still undergo testing and fixes, albeit later.

Create a separate category for apps that are no longer useful and should be retired immediately.

Ensure the inventory sheet is updated once tasks are completed. The aim is to minimize risk and streamline the testing and fixing of vulnerabilities.

3. Find and Analyze Your App Vulnerabilities

Once you’ve established a web application security blueprint, the next step is to identify and analyze vulnerabilities. Testing will likely reveal an excess of potential issues, but the challenge lies in prioritizing them based on severity.

While the Trustwave Global Security Report suggests an average of 20 vulnerabilities per application, not all are equally critical. For example, vulnerabilities like Injection and XSS pose higher risks compared to lower-priority issues like Unvalidated Redirects and Forwards.

To prioritize effectively, create a custom threat model tailored to your applications. Alternatively, utilize the OWASP Overall Risk Severity Scores, which provide a standardized framework for assessing vulnerabilities.

Check out our detailed blog on OWASP Top 10 web application vulnerabilities for detailed insights into threat agents, attack vectors, security weaknesses, technical impacts, and business impacts.

This comprehensive analysis will guide your prioritization efforts and ensure that critical vulnerabilities are addressed promptly.

4. Fix Critical and High Vulnerabilities

Fixing vulnerabilities in an application demands an understanding of the issue and code modifications, consuming significant time and resources. Attempting to eliminate all vulnerabilities at once can be daunting.

A more strategic approach is to prioritize vulnerabilities based on their impact on business and brand reputation.

Begin by addressing Critical and High vulnerabilities, ensuring developers focus solely on these issues.

Once these are resolved, move on to Medium and Low severity vulnerabilities. This phased approach optimizes resources and mitigates the most impactful risks first.

5. Deploy Virtual Patching / WAF

Real-world challenges often diverge from app security plans. Even small businesses may spend weeks identifying vulnerabilities and months rectifying them. According to the report, fixing critical vulnerabilities averages 250 days.

Can you afford to wait five months? Will hackers wait? Deploying interim fixes is essential to stop exploitation while long-term solutions are developed.

Virtual patching helps to reduce the window of vulnerability and enhance your security posture without the need for immediate software updates.

Get a Web Application Firewall (WAF): Traffic routed through a WAF is blocked if malicious. Advanced web application firewall even supports custom rules to block exploitation of any vulnerability, generic or app logic-specific. The WAF is critical to businesses with hundreds of applications and a shortage of resources to manage security risks.

The increasing adoption of virtual patching at the WAF level is proving beneficial for customers. In the past two quarters, AppTrana’s core ruleset blocked 40% of attacks, while custom rules blocked 60%.

This highlights the importance of managed services and tailored rulesets for security teams.

Restrict Functionality: If you choose to wait until all the applications are fixed, limit the app functionality. Restrictions like limited access to the user database, session timeout, and others can help prevent some of the attacks.

Irrespective of the fact that an application is vulnerable, secure, or protected through WAF, continue monitoring traffic for possible data leakage. Manual penetration testing is the best way to look for such loopholes. This will help you identify weak points and fix them before external exploitation.

Advanced Web Application Security Measures

Zero-day vulnerabilities, frequent code changes, third-party source code, app DDoS risks, and other unforeseeable circumstances make application security a difficult and never-ending project. However, implementing the above-mentioned web app security best practices, along with the following quick tips, will help you stay secure.

6. Continuous Application Monitoring  

Virtual patching via WAF not only provides benefits in terms of “time to fix” but also offers ongoing monitoring of web applications. It grants visibility into the vulnerabilities being blocked, their origins, and the actions of attackers before and after attempting exploitation.

These analytics contribute to building security intelligence and enhancing the efficiency of app security. Additionally, monitoring proves effective in countering application-layer DDoS attacks.

7. Automated Scanning + Penetration Testing

Automated app testing is vital for identifying vulnerabilities, but it may miss logical flaws. Supplement it with penetration testing by trained experts to simulate hacker-like attacks. Conduct penetration testing before transitioning apps from development to production, and consider automating testing for all infrastructure applications to enhance security.

8. Application Retirement

Over time, organizations accumulate a variety of applications, some of which may become outdated or no longer serve a purpose. These unused applications, often referred to as “shadow IT,” pose a significant security risk as they may contain vulnerabilities that go unnoticed.

Regularly identifying and retiring such applications reduces the attack surface and minimizes the risk of unauthorized access or exploitation.

9. Password Updates

Regularly updating passwords is a fundamental security practice aimed at mitigating the risk of unauthorized access to sensitive accounts. However, simply changing passwords is not sufficient; it’s equally important to follow industry best practices for password complexity, length, and storage.

Additionally, implementing multi-factor authentication (MFA) adds an extra layer of security by requiring users to verify their identity using multiple methods.

10. Log Forensics

Security logs provide valuable insights into the activities occurring within an application or system. By analyzing security logs, organizations can detect anomalous behavior, identify security incidents, and investigate breaches.

It’s essential to ensure that security logs are properly configured, securely stored, and regularly reviewed by qualified personnel to effectively monitor and respond to security threats.

11. Data Validation

Input validation is critical for preventing various types of attacks, such as SQL injection and XSS. By implementing a robust data validation model across all input fields, organizations can validate and sanitize user inputs to ensure they meet expected criteria.

This helps prevent malicious input from being processed by the application, reducing the risk of data breaches and other security incidents.

12. Privilege Restriction

Limiting user and application privileges is essential for minimizing the impact of security breaches. By implementing the principle of least privilege, organizations can ensure that users and applications only have access to the resources and functionality necessary to perform their roles.

This reduces the potential for unauthorized access, data exfiltration, and privilege escalation attacks.

13. Authentication

Authentication is the process of verifying the identity of users or systems accessing an application or network. Implementing strong authentication mechanisms, such as password-based authentication, multi-factor authentication (MFA), or biometric authentication, helps prevent unauthorized access and enhances overall security posture.

14. Content Policy

Developing and enforcing a content security policy (CSP) helps organizations control how resources are loaded and executed within web applications. A CSP defines rules for allowed content sources, script execution, and other security policies, helping mitigate the risk of client-side attacks like clickjacking.

15. File System Security

Securing the file system is essential for protecting sensitive data and preventing unauthorized access or modification. Implementing an unwritable file system or employing file system permissions effectively restricts access to critical files and directories, reducing the risk of data breaches and unauthorized changes to server content.

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