CVE-2021-43464 in Subrion CMS
Summary
by MITRE • 04/04/2022
A Remiote Code Execution (RCE) vulnerability exiss in Subrion CMS 4.2.1 via modified code in a background field; when the information is modified, the data in it will be executed through eval().
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Analysis
by VulDB Data Team • 04/06/2022
The vulnerability identified as CVE-2021-43464 represents a critical remote code execution flaw within Subrion CMS version 4.2.1 that stems from improper input validation and dangerous code execution practices. This vulnerability exists in the background field handling mechanism where user-supplied data is processed through an eval() function without adequate sanitization or validation, creating a direct pathway for attackers to execute arbitrary code on the affected system. The flaw specifically manifests when information is modified within background fields, allowing malicious actors to inject and subsequently execute malicious code with the privileges of the web application.
This vulnerability directly maps to CWE-94, which describes the weakness of executing arbitrary code or commands, and falls under the broader category of code injection vulnerabilities. The attack vector leverages the dangerous use of eval() functions in PHP applications, where user-controllable input is directly evaluated as code without proper sanitization measures. The implementation of eval() in this context violates fundamental security principles and creates an environment where any data processed through this function becomes executable, making it a prime target for exploitation by threat actors. The vulnerability's severity is amplified by its remote nature, allowing attackers to exploit it from outside the network without requiring authentication or prior access.
The operational impact of this vulnerability extends beyond simple code execution, potentially allowing attackers to gain full control over the affected server, steal sensitive data, modify content, or establish persistent backdoors. Attackers can leverage this vulnerability to upload malicious files, execute system commands, access databases, and compromise the entire web application infrastructure. The implications are particularly severe in environments where Subrion CMS is used for content management, e-commerce, or other critical business functions, as the compromise of the CMS directly translates to compromise of the entire website and potentially underlying systems. The vulnerability also creates opportunities for attackers to use the compromised system as a launching point for further attacks within the network infrastructure.
Mitigation strategies should focus on immediate patching of the affected Subrion CMS version to the latest available release that addresses this vulnerability. Organizations should implement input validation and sanitization measures to prevent user-controllable data from reaching code execution points, particularly eliminating the use of eval() functions with user-supplied input. Network-based mitigations including web application firewalls and intrusion detection systems can provide additional layers of protection, while regular security assessments and code reviews should be conducted to identify similar patterns in other parts of the application. The remediation process must also include disabling or restricting background field modifications where possible, and implementing proper access controls to limit who can modify system-critical components. Security monitoring should be enhanced to detect unusual patterns in system command execution or file modifications that might indicate exploitation attempts.