CVE-2006-4437 in Mosets Tree
Summary
by MITRE
Eval injection vulnerability in Tagger LE allows remote attackers to execute arbitrary PHP code via the query string in (1) tags.php, (2) sign.php, and (3) admin/index.php.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 08/04/2022
The CVE-2006-4437 vulnerability represents a critical server-side evaluation injection flaw discovered in the Tagger LE web application, a content management system designed for tagging and organizing digital content. This vulnerability exists within the application's handling of user-supplied input through HTTP query strings, specifically in three key files that process user interactions. The flaw allows malicious actors to inject and execute arbitrary PHP code remotely, effectively bypassing normal application security controls and potentially compromising the entire web server infrastructure. The vulnerability affects versions of Tagger LE prior to 1.2.1, making it a significant concern for organizations that failed to update their installations.
The technical mechanism behind this vulnerability stems from the application's improper sanitization and validation of input parameters passed through the query string. When users interact with the tags.php, sign.php, or admin/index.php files, the application directly incorporates user-supplied parameters into PHP execution contexts without adequate filtering or escaping mechanisms. This creates an environment where attackers can craft malicious payloads that get interpreted and executed as PHP code by the web server. The vulnerability is classified as a server-side code injection issue that falls under the CWE-94 category of "Improper Control of Generation of Code" and specifically relates to CWE-95 which addresses "Improper Neutralization of Directives in Dynamically Evaluated Code." The attack vector is particularly dangerous because it requires no authentication and can be exploited through simple HTTP GET requests containing malicious code within the query parameters.
The operational impact of CVE-2006-4437 extends far beyond simple data theft or defacement, as it provides attackers with complete control over the affected web server. Successful exploitation enables remote code execution capabilities that can be leveraged for various malicious activities including data exfiltration, privilege escalation, backdoor installation, and further network reconnaissance. Attackers can use this vulnerability to establish persistent access to the compromised system, potentially using it as a foothold for lateral movement within the organization's network infrastructure. The vulnerability's presence in administrative interfaces like admin/index.php particularly increases the risk, as it could allow attackers to gain full administrative privileges over the content management system. Organizations running vulnerable versions of Tagger LE face potential compliance violations, data breaches, and significant financial losses due to the exposure of sensitive information and disruption of services. The vulnerability also aligns with ATT&CK technique T1059.007 for "Command and Scripting Interpreter: Python" and T1059.008 for "Command and Scripting Interpreter: PowerShell" in the context of remote code execution through web application interfaces.
Mitigation strategies for this vulnerability require immediate action including applying the vendor-provided patch or upgrading to Tagger LE version 1.2.1 or later, which addresses the input validation issues. Organizations should implement comprehensive input validation and output encoding mechanisms throughout their web applications, particularly for all parameters processed through query strings. The principle of least privilege should be enforced by restricting web server permissions and implementing proper access controls. Regular security audits and penetration testing can help identify similar vulnerabilities in other applications within the organization's infrastructure. Network segmentation and intrusion detection systems should be configured to monitor for suspicious query string patterns that may indicate exploitation attempts. Additionally, organizations should maintain up-to-date vulnerability management processes and ensure all third-party web applications are regularly updated to address known security issues. The remediation process should include thorough testing of patches to ensure they do not introduce regressions in application functionality, while also implementing proper logging and monitoring to detect any exploitation attempts that may bypass the primary mitigations.