CVE-2020-36411 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 "Path for the {page_image} tag:" or "Path for thumbnail field:" parameters under the "Content Editing Settings" module.
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Analysis
by VulDB Data Team • 07/09/2021
This vulnerability resides within CMS Made Simple version 2.2.14, representing a critical stored cross-site scripting flaw that significantly undermines the security posture of affected systems. The vulnerability specifically targets the Content Editing Settings module where authenticated users can manipulate parameters related to image paths, creating a persistent threat vector that affects all users interacting with the compromised application. The flaw manifests when attackers exploit the "Path for the {page_image} tag:" and "Path for thumbnail field:" parameters, allowing them to inject malicious scripts that execute in the context of other users' browsers.
The technical mechanism behind this vulnerability stems from inadequate input validation and output sanitization within the CMS Made Simple framework. When administrators or authorized users enter crafted payloads into the specified path fields, the application fails to properly sanitize these inputs before storing them in the database. Subsequently, when the system renders these stored values in web pages, the malicious code executes within the browser context of any user who accesses the affected content. This represents a classic stored XSS attack pattern where the malicious payload persists in the application's data store and propagates to unsuspecting users without requiring additional interaction from them.
The operational impact of this vulnerability extends far beyond simple script execution, as it provides attackers with the capability to perform session hijacking, steal sensitive user credentials, redirect victims to malicious websites, or even deface the entire website. Given that the vulnerability requires authentication, it primarily affects privileged users who have administrative or content editing capabilities, but the potential for privilege escalation remains significant if attackers can leverage this vector to gain broader system access. The stored nature of the vulnerability means that the attack persists until manually removed from the database, creating a long-term threat that can affect multiple users over extended periods.
From a cybersecurity framework perspective, this vulnerability aligns with CWE-79: Improper Neutralization of Input During Web Page Generation, which specifically addresses the failure to properly escape or sanitize user-controllable data before incorporating it into web pages. The ATT&CK framework categorizes this as a technique under T1059.001 - Command and Scripting Interpreter: PowerShell, though more accurately it represents T1566.001 - Phishing: Spearphishing Attachment, as attackers would typically deliver the malicious payloads through crafted content submissions. Organizations should implement comprehensive input validation and output encoding measures, including the use of Content Security Policy headers, to mitigate the risk of such vulnerabilities. The vulnerability also highlights the importance of regular security updates and patch management, as CMS Made Simple has since released versions addressing this specific issue, emphasizing the need for timely remediation of known vulnerabilities.
Organizations utilizing CMS Made Simple should prioritize immediate remediation through official patch releases while implementing additional defensive measures such as web application firewalls and regular security audits. The vulnerability demonstrates the critical importance of validating all user inputs and properly escaping output data, particularly in content management systems where administrators frequently enter untrusted data into configurable fields. Security teams must also consider implementing monitoring solutions that can detect anomalous content submissions and maintain comprehensive backup strategies to quickly restore systems in case of successful exploitation attempts.