Web Application Security Best Practices

Technological advances driven by a digital revolution create opportunities for more and more creative forms of cyberattacks, making developers move toward more secure coding. What is web application security, and how can you secure your server?

Web application security doesn’t boil down to data encryption standards, proper authentication, and constant care for the application’s quality. It’s also about regularly assessing systems for vulnerabilities and developing a comprehensive security strategy that allows for rapid reactions. Why is it so important?

Common web application security vulnerabilities

Site-to-Site Scripting (XSS) – XSS is a security vulnerability that allows a hacker to inject client-side scripts into a Web page to gain direct access to critical information, impersonate a user, or trick a user into revealing crucial information.

SQL injection – This is a method by which an attacker exploits vulnerabilities in the way a database performs search queries. Attackers use SQL to access unauthorized information, modify or create new user permissions, or manipulate sensitive data. Consequences of the attack include, for example, unauthorized viewing of lists, deletion of tables, or unauthorized administrative access.

Denial of service (DoS) and distributed denial of service (DDoS) attacks – using different vectors, attackers can overload the target server or surrounding infrastructure with various types of attack traffic. When the server can no longer process incoming requests efficiently, it begins to act slowly and eventually refuses to serve incoming requests from legitimate users.

Cross-site request forgery (CSRF) – an attack that can result in unsolicited fund transfers, password changes, or data theft. It occurs when a malicious web application causes a user’s browser to perform an unwanted action on a site where the user is logged in. Once a user’s account is compromised, an attacker can extract, destroy or modify important information.

Data breach – is a general term referring to the disclosure of sensitive or confidential information and can occur as a result of malicious actions or by mistake. The scope of what is considered a data breach is quite broad and can refer to a few valuable records all the way up to millions of exposed user accounts.

What can you do to ensure you have a solid web application security strategy?

Here are some good examples of web application security best practices. Read on to find out more.

1. Secure access to the server

One of the main things that should be on your list is blocking remote access to the server. It should be encrypted, and server protection should be based on several levels of security (in particular, it is worth restricting SSH access or securing database ports).

Web application security best practices include:

• Restricting management access to specific IP addresses and configuring a firewall. Access to services such as SSH and MySQL should be limited, preferably by using a VPN. If the web application comes with an admin panel, login access should also be restricted. You can configure the web application’s firewall directly on the server or with a pre-configured set of rules managed by the cloud provider. (There are many of them on the market, and the most popular ones include AWS and DigitalOcean.)

A properly configured solution allows connections from the specified applications and servers only and prevents an application from initiating outgoing connections.

• Using SSH keys for authentication. Using SSH keys is more secure than using passwords. With this in mind, consider disabling password login entirely.

• Defining the number of failed login attempts. If you cannot apply the security measures above, or you need to access the application from multiple places (and you cannot use a VPN), secure the number of login attempts. For instance, if you use a Linux server, you can secure it with Fail2Ban. It’s also good to use such a solution for a web application with a login page to limit your exposure to brute force attacks.

2. Use Cloudflare DDoS protection

Speaking of firewalls, it’s worth using services such as Cloudflare to protect applications from critical vulnerabilities and threats. You can then automatically hide the IP address of a server, block certain countries from accessing a website, and spot automated traffic, to name a few options. Another advantage is blocking DDoS attacks aimed at overloading the website’s resources. 

Cloudflare also offers a free SSL certificate. Note that implementing SSL in your application is a must, so put it in place even if you don’t use Cloudflare’s solutions. You need HTTPS to protect personal data entries in the transmission layer.

3. Update the web application

Application code security vulnerabilities are another factor that reduces your web app security, especially because continuous technological advances bring new vulnerability. According to Web Application Vulnerabilities and Threats: Statistics for 2019, 82% of vulnerabilities were located in the application code. It’s important to ensure the quality of your code and test it for common security vulnerabilities to avoid potential attacks. 

To reduce the risk, always use the latest version of your programming language or framework and avoid using dangerous functions, such as eval and exec in PHP. Other things that can help are penetration testing and code reviews to identify flaws before the application is released.

4. Monitor the web application

What is web application security without knowing the key indicators for the success of your strategy? Monitoring the web application and the server where it is located makes it easier to detect anomalies and unwanted actions.

Tools, such as ELK Stack, logz.io, or Datadog may help to aggregate and parse your log data, so you will be able to find any errors (5xx, 4xx) that occurred to users and determine which part of the code caused it in a very easy way. Also, such tools automatically track actions performed on your website and are great for monitor anomalies such as rapid-fire login attempts. 

Monitoring the server is also necessary so that you know its status and important parameters, as well as spot suspicious login activity and low disk space alerts. Analyzing performance indicators and setting email or SMS alerts are all possible with tools such as Zabbix or Datadog. 

Here are metrics you can monitor: 

• Server load 
• Anomalies 
• Number of active users (malicious bot activity) 
• Number of login attempts and website visits 

5. Make regular backup copies

Critical website data can be lost for many reasons, so you should aim to back up as much data as possible — from databases and application code to files uploaded by application users. Make backups as often as possible and consider a cloud-based backup system that lets you store unlimited file versions. 

Data breaches in recent years have hit some of the most recognizable names online, such as Facebook and Uber, so you can see that the risk of data loss is real, despite seemingly the best protection (see the real-time cyberattack map). That’s why you need to be prepared for different scenarios; it’s not only hacker attacks that threaten important data. What if an employee deletes sensitive information? You see why it’s important to back up your database regularly.

Why is web security important?

The web application security best practices mentioned above can help you avoid common security threats and minimize the risk of attacks or data leaks. But keep in mind that even the most-prepared servers and multi-layered security approaches don’t fully ensure web application security. It’s worth using technologically advanced services such as AWS that provide an easy-to-consume infrastructure to manage servers on your behalf. 

Whether you choose a ready-made service or decide to set up security solutions yourself, always keep your finger on the pulse and control what happens with your application. Staying on top of the latest security trends and ways to efficiently remove possible web application vulnerabilities will keep you away from unpleasant surprises. That’s why it’s essential to constantly take care of the application environment and server condition, update apps frequently, and analyze trends. Anything that minimizes risk exposure is welcome.