Web Server Security – Beginner’s Guide

Web server security is a broad term covering the processes and solutions that keep web servers secure. Web server security encompasses three elements: host, network, and physical. For example, a comprehensive firewall can protect network connections, while unauthorized users are prevented from accessing a network by specific hardware or software components.

When discussing web server security, we can look at two key areas:

  • Securing a web server’s data
  • Securing the services that run on a web server

Access controls and operating system security protect a web server’s data, while antivirus software and firewalls safeguard the services that run on said server. The server’s data can be considered the most important of its assets, which is why it’s likely to be targeted in the majority of attacks.

Fortunately, encrypting information stored on the disk allows you to protect data. Intrusion detection tools can identify unauthorized users’ attempts to intrude, too, and help you respond to them in an effective way.

Ultimately, a user’s priority when using the internet is reaching a specific website as soon as possible. But they want to land on, and use, that website safely. That’s why web server security is such a critical topic, especially today, when hackers have access to highly sophisticated software.

The good news is that professionals in the information technology (IT) industry can take various steps to defend web servers from outside attacks. For instance, implementing a firewall is one of the most basic security measures: these run checks on all traffic going into and out of a web server, identifies traffic that may be dangerous or suspicious, then blocks it. But what else can you do?

In this guide, we’ll explore helpful ways to secure your web server, the best open-source tools, and more. But first, let’s start by discussing why web server security is so important.

Understanding Why Web Server Security Matters

One of the most important parts of having a website is ensuring effective security — particularly when operating a web server. When a web server is unprotected, it can easily become the target of an attack, and hackers could steal sensitive data from it in no time.

Web servers are responsible for numerous tasks, including the storage, processing, and delivery of web pages (as well as other forms of online content). Additionally, web servers are essential for hosting and serving a variety of data in diverse formats. For example, video files, executable programs, and audio files.

With that in mind, a web server should be defended against unauthorized users to ensure that all information on it remains safe. That reduces the risk that anyone can access, modify, disclose, or even destroy data on the server.

What are the Most Common Web Server Weaknesses?

Web servers deliver the web content you browse daily, and they’re designed to be as robust, efficient, and secure as possible. However, they still have a number of vulnerabilities that affect their (and their users’) security.

Common weaknesses include command injection, cross-site scripting (XSS), and SQL injection. While some of these are easy to take advantage of, exploiting others requires a little more work and detail. Below, we’ll take a closer look at these security threats and why they’re so dangerous.

DoS Attacks

When someone launches a denial of service (DoS) attack, they are trying to prevent users from accessing the targeted web server or network resource as they usually would.

These focus on a specific web server or resource: the attacker floods the target with high levels of traffic until it becomes unavailable to genuine users. That can be especially damaging for online retail sites, as they would be unable to process transactions.

Perpetrators launch DoS attacks using viruses, bots, or other tools that consume the target’s CPU or network capacity. They can also initiate attacks with computers or networks that have been infected by viruses or other harmful software.

Cross-Site Scripting Attacks

During cross-site scripting (XSS) attacks, perpetrators inject code executed by the user’s web browser. The code responsible is typically seized when the user’s cookies are sent to the web server.

Perpetrators tend to use XSS attacks to undertake actions on behalf of a user, which allows them to access a user’s current session.

SQL Injection Attacks

An SQL injection is a form of attack capable of overrunning a database. The attacker will input malicious code into the information entry fields on a data-driven application or website.

Once the code is injected into the database of a website or application, the attacker can access data that would normally be out of their reach. They can view and tamper with this information, which could allow them to manipulate and expose sensitive data.

How to Keep Your Web Server Secure

In our interconnected world, companies of all sizes must take web server security seriously to stay safe. Cybercriminals have a wide variety of techniques to choose from, so it’s vital that you implement the necessary measures to secure your web server.

Attackers can cause extensive damage to any business, but comprehensive security can make their work much more difficult. Here are three simple steps to keep your web server secure.

Eliminate Redundant Services

Standard operating system setups aren’t secure, often including unused network services, like remote registry or print server services. These services open additional ports, increasing vulnerability to malicious attacks. Deactivate and disable these services to prevent them from auto-starting after a reboot, improving server performance and freeing hardware resources.

Control Remote Access

While less practical today, server administrators should ideally access web servers directly. If remote access is necessary, secure it with tunneling and encryption, use security tokens and single sign-on tools, limit access to certain IPs and accounts, and avoid using public computers or networks for remote server access.

Distinguish Development and Production Environments

Developers often use production servers for quicker application development, leading to public exposure of unfinished versions or content in directories like /test/ or /new/. These early-stage applications, with various vulnerabilities and poor exception handling, are susceptible to exploitation. Development and testing should occur on isolated servers, disconnected from live data and databases.

Isolate Web Application Data

Web applications and scripts should reside on a separate partition or drive from the operating system and other system files. Hackers accessing the web root can exploit vulnerabilities and gain access to the entire disk, including system files, allowing them to execute commands and control the server.

Manage Permissions and Privileges

Properly assigning permissions to files and network services is crucial for security. In case of a network service compromise, limiting privileges can prevent further exploitation. Ensure minimal necessary access for network services and anonymous users for web applications and databases.

Install Security Patches

Fully patched software doesn’t guarantee complete security, but it’s vital to regularly update the operating system and software with the latest patches. Many hacking incidents result from exploiting unpatched servers.

Monitor and Audit Server Logs

Keep web server logs in a separate area and regularly check them, including network services, website access, database server, and operating system logs. Investigate unusual log entries immediately to address potential security issues.

Secure User Accounts

Disable unused default accounts created during operating system installations. Check accounts added by software installations, adjust permissions as necessary, rename built-in administrator accounts, and ensure each administrator has a unique account without sharing credentials.

Remove Unused Modules and Extensions

Disable unnecessary Apache modules and limit IIS to essential application extensions, restricting their HTTP verb usage. This step reduces risks of targeted attacks on these modules.

Utilize Provided Security Tools

Use security tools like URL scan for IIS and mod_security for Apache. While setup can be complex and time-consuming, especially with custom applications, these tools add significant security enhancements.

Top Open Source Security Solutions for Web Servers

You can choose from a wide range of open source security tools to protect your web server. These can help defend you against common threats and provide users with a safer experience.

Here are the best open source security tools for web servers available.

Nmap

Nmap (Network Mapper) is an open-source solution for security audits, discovering networks and hosts, and exploring networks. You can use Nmap to scan networks on a bigger scale, but it’s suitable for single hosts too.

Snort

Snort is built for preventing network intrusion and identifying potential threats. It can run traffic analysis in real-time, using both protocol analysis and pattern matching to pinpoint signs of possible issues in network traffic.

Metasploit

With Metasploit, you can get an insight into security weaknesses that will make it easier to protect your web server.

Metasploit helps in IDS signature development and penetration testing, so you can learn more about vulnerabilities and take action to address them before they are exploited by attackers.

Sqlmap

Sqlmap is an open-source tool for automated security testing: you can automatically identify and exploit SQL injection vulnerabilities that would allow attackers to take a database over. This can be an effective way to fix weaknesses before someone else discovers them.

OpenVAS

With OpenVAS, you can run a comprehensive network scan to detect issues (such as XSS vulnerabilities). OpenVAS is free to use, and companies across the globe use it to maintain a secure infrastructure.

Summary

Operating a website of any kind requires a good web server. The site’s core files are hosted on a computer and delivered to the users who land on your site, so ensuring effective web server security is paramount to reduce risks. Otherwise, attackers could target your site, access sensitive data, and disrupt your operations.

We hope this guide to web server security has helped you understand some of the risks out there and the best ways to stay safe.