Headless CMS solutions growing throughout the content management landscape promised frictionless API-driven content delivery. However, as more companies use Headless CMS for their websites and applications, new intrusions emerged most recently, content injection attacks. Hackers exploit vulnerabilities with the API routing, too many user-input fields, or an excess of database queries and renders, allowing them to insert unauthorized content into an application. These hackers, who rely upon content injection attacks, can overwrite valid, legitimate content so pages become unreadable, filled with erroneous data, or worse, erroneous data that the end-user does not know is erroneous.
Regarding the potential for content injection in a Headless CMS, I would presume that developments would have to be made around securing input fields (form validation), the API, establishing authentication (access control), and even the creation of logging to monitor intrusions post-fact. If a developer can control what’s getting in and who owns what’s being saved and altered, they can prevent corruptions of digital experiences from ever happening in the first place or from being rendered faulty at the source.
Understanding Content Injection Attacks in Headless CMS
WordPress alternatives open-source solutions, like Headless CMS platforms, offer greater flexibility but also require robust security measures to prevent vulnerabilities. Content injection vulnerabilities occur when, for example, a nefarious actor seizes control of a form field or an API request, and where certain expectations are entered into a Headless CMS, something different occurs instead. This is more vulnerable with a Headless CMS because it operates solely on API calls. There is no default CMS that is publicly facing where such protections could be. Three of the most common forms of content injection include cross-site scripting, SQL injection, and template injection.
For example, cross-site scripting (XSS) enables malicious individuals to access your content fields and inject scripts that run in the web browsers of your users allowing them to steal passwords or modify how web pages operate. Another example is SQL injection, which enables bad actors to submit malicious SQL queries through API requests or web forms. This takes advantage of the relationship between a web application and its database and reveals confidential data. Finally, template injection occurs when hackers have access to your rendering engine and execute unapproved actions. Being able to avoid the disastrous effects of a content injection attack, loss of user trust, compromised company reputation, even problems with compliance and regulatory bodies should inspire an organization to protect its Headless CMS from this exploit.
Implementing Strong Input Validation and Sanitization
Probably the ideal way to prevent content injection is strict input validation. Everything that goes into the Headless CMS via user entry, API requests, or update actions needs to be validated before storage or rendering at a strict level. For example, using a whitelist so that only expected content and ways of receiving it come through are granted access and everything else denied (which should be the case when an attacker tries to insert script or code to the Headless CMS). In addition, sanitation should occur to make scripts useless removing certain HTML tags, escaping certain characters, and sanitizing every single user data entry field to avoid script execution. When input validation and content sanitation fail to permit such an occurrence, the likelihood of a content injection attack is significantly decreased, and only the validated, sanitized data is rendered and processed.
Securing API Endpoints to Prevent Unauthorized Access
A Headless CMS utilizes API endpoints to retrieve and modify content, so API security is critical to prevent content injection attacks. If the API is set up incorrectly, it can allow anyone to modify content which means that malicious users can inject their content into saved content that was never intended to be changed. Authentication and authorization are additional security measures for APIs. For instance, with things like OAuth 2.0 and JSON Web Tokens (JWT), only specific applications and requested users can access the CMS. In addition, Role-Based Access Control (RBAC) is essential for determining who can edit certain content fields and who can legitimately change this information. Other mechanisms include rate limiting and anomaly detection, the latter flagging bizarre behavior too many attempts to change something or too many attempts to access an API without permission. If a company can monitor its APIs in real time, it can also stop injection attacks from occurring by seeing and refusing efforts before it’s too late.
Using Content Security Policies (CSP) to Block Malicious Scripts
A Content Security Policy (CSP) is a web security configuration that reduces cross-site scripting (XSS) attack vulnerability. CSP policies specify where a particular webpage can run a given script. Thus, if CSP does not acknowledge a particular source from which the script originates, it guarantees that the script will not run within the browser of the end-user. Thus, for any Headless CMS application that renders and ports content to multiple digital endpoints, a strong CSP policy reduces the risk that content renders in the first place. Companies need to establish CSP policies that render all inline scripts nonexistent and specify where JavaScripts can render, as well as who can render code creation/injections or rendering/executions.
Equipped with a robust CSP policy, the company now has another barrier to potential attacks: it’s more challenging to execute malicious scripts and a new protective layer against injection attempts.
Enforcing Secure Database Queries to Prevent SQL Injection
Of all the vulnerabilities associated with content injection, none can be more fatal than SQL injections. An SQL injection allows a nefarious user to alter the command of a database query and pull information that would not typically be available to that user. Thus, a Headless CMS must make sure that injection-type vulnerabilities are avoided in regard to access through querying since it’s dependent on a backend database.
Thus, developers should implement prepared statements and parameterized queries, meaning that there should never be user input as a database command. For example, assume a developer is creating a database query that needs to use values from the end user. One would want to create it in real-time to accept those values, but instead, one wants to create a template/standard and bind values to that template/standard so that even a hacker cannot inject illegitimate SQL commands. In addition, database access controls regulate who can change which data. Provided the database is limited to necessary users and the API client, the likelihood of someone being able to change data when they shouldn’t is reduced.
Monitoring and Logging for Early Threat Detection
Content injection attacks will never happen if someone is always watching and logging. A Headless CMS has a logging feature to identify who changes what and when (and which API requests) and how people are accessing the CMS which could be a red flag for security negligence as well. In addition, through behavioral analytics, negative trends can be assessed like too many failed logins, changes to content that were approved to remain static, and even too many API requests from suspicious geo-locations.
If something is off, fail-safes can lock people out, issue warnings, or prompt secondary authorization to prevent malicious behavior. The advantage of having an active monitoring service is that if the business does not take precautions against a content injection vulnerability, it will be instantly notified how to defend itself and it won’t have evil intruders breaking into its Headless CMS.
Strengthening Authentication to Prevent Unauthorized Content Modifications
An unobtrusive authentication system keeps prying eyes and unscrupulous hands from accessing what has already been inputted. When the authentication system is accessible, hackers can more easily access the Headless CMS to add their nefarious headlines.
Thus, MFA should be implemented for every CMS super admin and creator. This acts as a second line of defense in addition to password protections. In addition, a smart authentication system assesses logins against activity (time of access, device legitimacy, geofencing, and volume of access). Restricting access via rotating API keys and ephemeral tokens makes stolen credentials eventually useless; should a hacker get a key, it’s only good for a limited time. Robust authentication prevents accessing what shouldn’t be accessed and, therefore, renders less motivation to carry out injection attacks on sensitive data.
Conclusion
Rather than one solution to avoid content injection exploits within a Headless CMS, everything from input sanitization to API endpoint security to content security policy to prepare statements for SQL databases to vulnerability discovery and breach detection is needed. If these fail, however, the organization is left susceptible to unwanted injection, tampered content, and possibly lost revenue while attempting to regain trust from third-party entities. In the end, accessibility authentication, API access monitoring and logging, and frontend input validation safeguard a Headless CMS from malicious injections. With so much exposure on the Internet, organizations looking to migrate to a Headless CMS solution must do so with caution.
