CVE-2020-21482 in RGCMS
Summary
by MITRE • 09/16/2021
A cross-site scripting (XSS) vulnerability in RGCMS v1.06 allows attackers to obtain the administrator's cookie via a crafted payload in the Name field under the Message Board module
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Analysis
by VulDB Data Team • 09/19/2021
This cross-site scripting vulnerability exists within RGCMS version 1.06, specifically within the Message Board module where user input is not properly sanitized before being rendered back to users. The flaw manifests when an attacker crafts a malicious payload containing javascript code within the Name field, which then gets executed in the context of an administrator's browser session. This represents a classic stored XSS vulnerability where the malicious script is permanently stored on the server and executed whenever the affected page is accessed. The vulnerability is particularly dangerous because it allows attackers to steal administrator cookies, which contain session information that grants full administrative privileges to the compromised account. The attack vector leverages the lack of input validation and output encoding in the message board's name field processing, creating an environment where malicious javascript can be injected and persistently executed. This vulnerability directly maps to CWE-79 which defines cross-site scripting as the failure to properly encode output, and aligns with ATT&CK technique T1531 which involves using compromised credentials to gain unauthorized access to systems.
The operational impact of this vulnerability extends beyond simple cookie theft, as it provides attackers with complete administrative control over the CMS system. Once an attacker obtains the administrator's session cookie, they can perform any action within the CMS, including modifying content, adding new users, changing system configurations, and potentially accessing sensitive data stored within the database. The persistent nature of stored XSS means that even if the initial injection is not immediately exploited, the malicious payload will continue to execute whenever administrators view the message board, creating a long-term attack vector. The vulnerability demonstrates poor input validation practices and highlights the critical importance of implementing proper output encoding mechanisms to prevent malicious code execution. Attackers can leverage this vulnerability to establish persistent backdoors, exfiltrate sensitive information, or use the administrative access to pivot into broader network infrastructures. The impact is particularly severe for content management systems where administrators frequently interact with user-generated content, as the attack surface expands to include all administrative functions.
Mitigation strategies for this vulnerability should focus on implementing comprehensive input validation and output encoding measures throughout the application. The most effective immediate fix involves sanitizing all user input, particularly in fields where HTML content might be rendered, and ensuring that any potentially malicious script tags are properly escaped or removed. Implementing Content Security Policy headers can provide additional protection against XSS attacks by restricting the sources from which scripts can be loaded. Regular security audits and code reviews should be conducted to identify similar input validation gaps throughout the application. The implementation of proper parameterized queries and input sanitization libraries can prevent similar vulnerabilities from occurring in other parts of the system. Organizations should also consider implementing web application firewalls to detect and block suspicious payloads attempting to exploit XSS vulnerabilities. Regular patch management and security updates are essential to address known vulnerabilities in third-party components. The incident should trigger a comprehensive review of all user input handling processes, with particular attention to areas where user-generated content is displayed. Security training for developers should emphasize secure coding practices and the importance of validating and sanitizing all external inputs to prevent injection attacks.