CVE-2020-36410 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 "Email address to receive notification of news submission" parameter under the "Options" 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 code into the application's configuration settings. The vulnerability specifically resides in the "Options" module where administrators can configure notification email addresses for news submissions. When an attacker with valid credentials manipulates the "Email address to receive notification of news submission" parameter, the malicious payload gets stored within the application's database and subsequently executed whenever the affected page is rendered to any user with appropriate privileges. This stored nature of the vulnerability means that the malicious code persists even after the initial injection, making it particularly dangerous as it can affect multiple users over time.
The technical exploitation of this vulnerability follows the typical stored XSS attack pattern where input validation fails to properly sanitize user-supplied data before it is stored and subsequently rendered in the application's output. The flaw occurs because the application does not adequately filter or escape special characters in the email address field, allowing attackers to inject HTML tags or JavaScript code that gets executed in the context of other users' browsers. This vulnerability falls under CWE-79 which specifically addresses cross-site scripting flaws, and it aligns with ATT&CK technique T1566.001 which covers the use of malicious emails or web content to deliver payloads to users. The attack requires only authenticated access, which significantly lowers the barrier to exploitation since most CMS platforms have relatively permissive access controls for administrative functions.
The operational impact of this vulnerability extends beyond simple script execution as it provides attackers with persistent access to the application's administrative environment. Once exploited, attackers can manipulate the configuration settings, potentially redirecting notifications to malicious addresses, or they can inject more sophisticated payloads that could lead to complete system compromise. The vulnerability affects any user who has access to the Options module, which typically includes administrators and privileged users, making it a significant threat to the overall security posture of the CMS. The stored nature means that even if the original attacker's session ends, the malicious code continues to execute, potentially allowing for extended periods of unauthorized access and data manipulation. This vulnerability could also serve as a stepping stone for attackers to escalate privileges or establish persistent backdoors within the organization's web infrastructure.
Mitigation strategies for this vulnerability should focus on immediate patching of the CMS Made Simple application to version 2.2.15 or later, which contains the necessary fixes for this XSS vulnerability. Organizations should also implement input validation and output encoding mechanisms to prevent similar issues in the future, ensuring that all user-supplied data is properly sanitized before being stored or rendered. The principle of least privilege should be enforced by limiting administrative access to only those users who absolutely require it, reducing the attack surface. Additionally, implementing content security policies and regular security scanning of web applications can help detect and prevent similar vulnerabilities. Network monitoring should be enhanced to detect unusual traffic patterns that might indicate exploitation attempts, and regular security audits should verify that all CMS components are properly updated and configured according to security best practices.