CVE-2020-36416 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 "Create a new Design" parameter under the "Designs" module.
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Analysis
by VulDB Data Team • 07/09/2021
The vulnerability CVE-2020-36416 represents a critical stored cross-site scripting flaw within CMS Made Simple version 2.2.14 that fundamentally compromises the security posture of affected systems. This vulnerability exists within the administrative interface of the content management system, specifically within the "Designs" module where users can create new designs. The flaw allows authenticated attackers who have already gained access to an administrative account to inject malicious scripts that persist in the system and execute whenever the affected page is loaded. The vulnerability is classified as a stored XSS attack because the malicious payload is permanently stored on the server and executed against other users who view the affected content, rather than being reflected in a single request.
The technical implementation of this vulnerability stems from insufficient input validation and output sanitization within the "Create a new Design" parameter processing. When administrators create new designs through the web interface, the application fails to properly sanitize user-supplied input before storing it in the database. This lack of proper input validation creates an opening for attackers to inject malicious HTML or JavaScript code that gets stored in the system and executed in the context of other users' browsers. The vulnerability specifically affects the design creation functionality, which is commonly used by administrators to customize the appearance and behavior of websites built on the CMS platform. The flaw operates under CWE-79 which categorizes cross-site scripting vulnerabilities as a result of inadequate input validation and output encoding.
The operational impact of this vulnerability extends far beyond simple script execution, as it can enable attackers to perform a wide range of malicious activities against the compromised system and its users. An attacker could leverage this vulnerability to steal session cookies, redirect users to malicious websites, modify website content, or even escalate privileges within the CMS environment. The stored nature of the vulnerability means that the malicious code remains active until manually removed by administrators, potentially affecting multiple users over extended periods. This vulnerability particularly threatens organizations that rely heavily on CMS Made Simple for their website infrastructure, as it provides attackers with a persistent foothold that can be exploited to compromise the entire web application environment. The attack vector is particularly concerning because it requires only administrative access, which is often less frequently monitored than public-facing vulnerabilities, making detection more difficult.
Organizations affected by this vulnerability should implement immediate mitigations including updating to CMS Made Simple version 2.2.15 or later, which contains the necessary patches to address the XSS vulnerability. Additionally, administrators should conduct thorough security reviews of all design elements and user inputs to identify any existing malicious code that may have been injected prior to the patch installation. The mitigation strategy should also include implementing proper input validation and output encoding mechanisms throughout the application, particularly for all user-supplied content that gets stored in the database. Security monitoring should be enhanced to detect unusual administrative activities and potential attempts to inject malicious scripts into the design creation parameters. Organizations should also consider implementing web application firewalls and content security policies to add additional layers of protection against similar vulnerabilities. This vulnerability demonstrates the importance of maintaining up-to-date software versions and implementing proper security controls for administrative interfaces, as it aligns with ATT&CK technique T1059.001 for command and scripting interpreter and T1071.001 for application layer protocol. The vulnerability also highlights the need for regular security assessments of content management systems to identify and remediate stored XSS vulnerabilities that can persist for extended periods and affect multiple users.