Backend Security Risks and Tips on How to Prevent Them

1. Data injection risks

Data injection is the use of queries to hack your web application servers. Cyber attackers initiate a query to your system to retrieve sensitive data. In the absence of measures in place to check the origin and authenticity of the query, your system blindly processes the query and provides the requested information to the attackers.

A great way to prevent data injection is to ensure that your backend applications don’t accept or process inputs from unauthorized and unverified sources. That way, requests from unverified sources will be blocked or go unattended.

2. Lack of authentication security

Web application backends consist of multiple services with authentication requirements, databases as well as console/OS level access have logins, and all of these services run directly on the operating system layer. Therefore, maintaining authentication security is crucial—otherwise, any vulnerability entering the system can lead to the whole operating system being compromised.

For example, when it comes to the web server, restricting logins to certain users or IP addresses, using HTTP authentication on development areas, or using automated brute force detection systems (that automatically ban offending IP addresses) helps a lot.

3. Lack of vulnerability scanning

Scanning for vulnerabilities is another neglected safeguard regarding web applications, from frontend to backend. Only when you scan will you know what is and isn't vulnerable.

Scanning is often thought of as a difficult and time consuming task, but modern tools have made it possible to scan automatically and with a low amount of effort. Using online vulnerability scanners and other tools like Nikto or OpenVAS helps you stay on top of your web application's safety by automatically scanning and generating reports for you to review.

4. Lack of encryption between frontend and backend

Communication between your web application's frontend and backend is what drives your web application. And this communication often goes over the internet unencrypted, as the software in use is often built without encryption in mind.

Man-in-the-middle-attacks apply not only between clients and web applications, but can also poison or steal requests from your frontend or backend, and transmit them to the attacker. While this is a more sophisticated type of attack, it's still quite possible for someone who wishes to target your web application.

Encrypting requests between the frontend and backend is a simple yet critical solution for preventing these attacks.

5. Lack of centralized log management

With multiple backends, services and distributed servers (sometimes even across different public/private clouds and access levels), modern web applications call for a centralized logging system, to which all services can write their log files.

This allows for further monitoring and logging of errors, unauthorized entry attempts (such as failed login alerts), and other information which can be used to improve performance as well.

A lack of centralized logging often leads to unnecessary privileges being made available to team members, or simply due to the scale of things, log files getting overlooked.

This can be particularly dangerous if the log files indicate attacks against your web application's backend, and their neglect means an attack isn't effectively blocked in time.

6. SSL misconfigurations and lack of monitoring

Using SSL certificates has become a norm for the modern internet. Most browsers and search engines give priority to websites with SSL certificates, and display various forms of alerts and errors when browsing websites with insecure, misconfigured or expired SSL certificates.

Be sure to monitor your SSL certificate and configure it correctly. Ensuring your certificates are valid is the first step, noting that they're set up with strong ciphers and that secure and modern TLS versions are in use on the server-side. This will go far in maintaining that your web application's backend is communicating securely with its frontend.

7. Sensitive data exposure

Applications often cache or hold data in temporary locations for customers to access. This data can be used to improve performance or simply allow users to download their files, but if data isn't removed in time—or isn't restricted to the specific customer—it can allow attackers to find and download this sensitive information.

For example, if a user uploads his avatar onto a web application, the web application stores it in a publicly accessible folder for the image to render. However, if the folder isn't well secured, an attacker can locate the folder and download all the user's avatars.

Securing folders and other publicly accessible information is a must. Also, performing self-scans by using Google Dorks enables you to quickly find public information crawled by search engines.

8. Outdated/end-of-life software components

Multiple software components are used to make any web application work, with web servers, databases and other software helping to improve performance.

With all these bits of software in use, the security of each individual application has to be considered.

For example, if your web server is vulnerable, it can cause your entire web application to be vulnerable—by accepting inputs from users which can expose sensitive areas of your web application.

As we shared in our 'Why software gets hacked' blog post, having any outdated or end-of-life software component on the public internet is a huge risk, especially with tools like Shodan available, allowing users to search for servers running specific versions of software. This can make you and your web application an easy target when running outdated and end-of-life software.