CVE-2020-36409 in CMS Made Simple
Summary
by MITRE • 07/03/2021
A stored cross scripting (XSS) vulnerability in CMS Made Simple 2.2.14 allows authenticated attackers to execute arbitrary web scripts or HTML via a crafted payload entered into the "Add Category" parameter under the "Categories" module.
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Analysis
by VulDB Data Team • 07/09/2021
This vulnerability represents a critical stored cross-site scripting flaw in CMS Made Simple version 2.2.14 that enables authenticated attackers to inject malicious scripts into the application's database through the Categories module. The vulnerability specifically affects the "Add Category" parameter where user input is not properly sanitized or validated before being stored and subsequently rendered in subsequent page requests. When an administrator or authenticated user views the category list, the malicious payload executes in their browser context, potentially leading to session hijacking, credential theft, or further compromise of the affected system. The stored nature of this vulnerability means that the malicious code persists in the database and affects all users who view the affected content, making it particularly dangerous in multi-user environments where administrators frequently access category management interfaces.
The technical implementation of this vulnerability stems from inadequate input validation and output encoding practices within the CMS Made Simple application. When administrators create categories through the web interface, the application fails to properly escape special characters or validate the input against a whitelist of acceptable characters. This allows attackers to inject HTML tags, JavaScript code, or other malicious content that gets stored in the database without proper sanitization. The vulnerability aligns with CWE-79 which specifically addresses cross-site scripting flaws, and more precisely with CWE-80 which covers the storage of untrusted data without proper validation. The attack vector requires authentication privileges, making it a server-side vulnerability that can be exploited by insiders or compromised accounts, though it can also be leveraged by attackers who have gained initial access through other means.
The operational impact of this vulnerability extends beyond simple script execution as it can enable attackers to establish persistent access to the CMS environment. Successful exploitation could allow attackers to modify or delete category data, potentially disrupting content management operations, or to inject additional malicious payloads that could escalate privileges within the CMS. The vulnerability affects the entire CMS Made Simple ecosystem and can be particularly damaging in environments where the CMS is used for sensitive content management or where administrators have elevated privileges. Attackers could leverage this vulnerability to create backdoor access points, manipulate content, or use the compromised system as a staging area for further attacks against the broader network infrastructure. The persistent nature of stored XSS means that even after the initial compromise, the malicious code continues to execute until the database entries are manually removed or the application is patched.
Mitigation strategies for this vulnerability require immediate patching of the CMS Made Simple application to version 2.2.15 or later where the vulnerability has been addressed through proper input validation and output encoding. Organizations should implement comprehensive input sanitization measures that validate all user-supplied data against strict whitelists and ensure that all stored data is properly escaped before rendering in HTML contexts. Network segmentation and privileged access controls should be enforced to limit the potential impact of authenticated attacks, while regular security audits should verify that no malicious content has already been injected into the system. Additionally, implementing web application firewalls and content security policies can provide additional layers of protection against similar vulnerabilities. The remediation process should include thorough database scanning to identify any previously injected malicious content and comprehensive monitoring for suspicious activities that might indicate exploitation attempts. This vulnerability highlights the critical importance of maintaining up-to-date security patches and proper input validation practices in web applications, as it demonstrates how a single unvalidated input field can create a persistent security risk for the entire system.