CVE-2020-27377 in CMS Made Simple
Summary
by MITRE • 06/02/2021
A cross-site scripting (XSS) vulnerability was discovered in the Administrator panel on the 'Setting News' module on CMS Made Simple 2.2.14 which allows an attacker to execute arbitrary web scripts.
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Analysis
by VulDB Data Team • 06/05/2021
This cross-site scripting vulnerability exists within the administrative interface of CMS Made Simple version 2.2.14 specifically within the 'Setting News' module. The flaw represents a classic persistent XSS attack vector that enables malicious actors to inject and execute arbitrary JavaScript code within the context of an administrator's browser session. The vulnerability is particularly concerning because it targets the administrator panel, which typically operates with elevated privileges and access to sensitive system functions. When an administrator visits a page containing malicious script code, the script executes in their browser with full administrative privileges, potentially allowing attackers to perform unauthorized actions such as modifying content, accessing sensitive data, or even compromising the entire system.
The technical implementation of this vulnerability stems from insufficient input validation and output encoding within the news settings module. Attackers can craft malicious payloads that are stored in the system and subsequently executed whenever the affected administrative interface is accessed. This type of vulnerability falls under CWE-79 - Improper Neutralization of Input During Web Page Generation, which is a fundamental weakness in web application security. The vulnerability is classified as a persistent XSS attack because the malicious code is stored on the server and executed every time the vulnerable page is loaded, rather than being reflected in a single request. This characteristic makes the attack more dangerous and persistent compared to reflected XSS variants.
The operational impact of this vulnerability is significant as it provides attackers with direct access to the administrative functions of the CMS. An attacker who successfully exploits this vulnerability can manipulate news content, modify system settings, create or delete users, and potentially gain access to other administrative modules within the CMS. The attack can be executed without requiring the administrator to click on any malicious links or perform specific actions, as the malicious script executes automatically when the vulnerable page is loaded. This automated execution increases the likelihood of successful exploitation and reduces the attack surface complexity. The vulnerability also aligns with ATT&CK technique T1059.007 - Command and Scripting Interpreter: JavaScript, which describes how adversaries use JavaScript to execute malicious code within web browsers.
Mitigation strategies for this vulnerability include immediate patching of the CMS Made Simple installation to version 2.2.15 or later, which contains the necessary security fixes. Organizations should also implement proper input validation and output encoding mechanisms throughout the application, particularly in administrative interfaces where user-supplied data is processed. Implementing Content Security Policy (CSP) headers can provide additional protection against XSS attacks by restricting the sources from which scripts can be loaded and executed. Regular security audits and penetration testing of administrative interfaces should be conducted to identify similar vulnerabilities. Additionally, implementing web application firewalls and input sanitization measures can provide defense-in-depth protection against similar XSS vulnerabilities. The vulnerability demonstrates the critical importance of securing administrative interfaces and maintaining up-to-date software versions to protect against known security flaws.