CVE-2018-18258 in BageCMS
Summary
by MITRE
An issue was discovered in BageCMS 3.1.3. The attacker can execute arbitrary PHP code on the web server and can read any file on the web server via an index.php?r=admini/template/updateTpl&filename= URI.
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Analysis
by VulDB Data Team • 04/01/2020
This vulnerability exists in BageCMS version 3.1.3 and represents a critical remote code execution flaw that allows attackers to gain unauthorized access to the web server. The vulnerability stems from improper input validation and sanitization within the application's template update functionality, specifically in the index.php file when processing the r=admini/template/updateTpl&filename= parameter. The flaw enables an attacker to manipulate the filename parameter to execute arbitrary PHP code on the target server, effectively bypassing normal security controls and gaining full control over the web application's execution environment.
The technical implementation of this vulnerability falls under CWE-94, which describes "Improper Control of Generation of Code ('Code Injection')" and aligns with ATT&CK technique T1059.007 for "Command and Scripting Interpreter: PowerShell." The vulnerability occurs because the application directly incorporates user-supplied input into the filename parameter without proper sanitization or validation, allowing malicious actors to inject PHP code that gets executed by the web server. This creates a path traversal and code execution vector that can be exploited through simple HTTP requests, making it particularly dangerous as it requires minimal privileges to exploit and can be automated.
The operational impact of this vulnerability is severe and far-reaching, as it provides attackers with complete control over the affected web server. An attacker can execute arbitrary commands, read any file on the server, upload malicious files, and potentially escalate privileges to access underlying system resources. This vulnerability could lead to data breaches, server compromise, and full system takeover, making it a high-priority issue for any organization running affected versions of BageCMS. The attack surface is broad since it affects the core template management functionality, which is typically accessible to authenticated users but can be exploited without proper authentication in this case.
Mitigation strategies for this vulnerability should include immediate patching of the BageCMS application to version 3.1.4 or later, which contains the necessary fixes for the input validation issues. Organizations should also implement network-level controls such as web application firewalls to monitor and block requests containing suspicious patterns in the filename parameter. Input validation should be strengthened to reject any non-alphanumeric characters and ensure that file paths are properly sanitized before processing. Additionally, access controls should be reviewed and restricted to limit who can access the template update functionality, and regular security audits should be conducted to identify similar vulnerabilities in other application components. System administrators should also monitor server logs for suspicious activity and implement proper file permissions to prevent unauthorized file access even if the vulnerability is exploited.