CVE-2009-3423 in PaoLink
Summary
by MITRE
login.php in Zenas PaoLink 1.0, when register_globals is enabled, allows remote attackers to bypass authentication and gain administrative access by setting the login_ok parameter to 1.
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Analysis
by VulDB Data Team • 12/07/2024
The vulnerability identified as CVE-2009-3423 affects the Zenas PaoLink 1.0 web application, specifically targeting the login.php script when the PHP configuration parameter register_globals is enabled. This flaw represents a classic example of insecure direct object reference and improper input validation, creating a path for remote attackers to manipulate application behavior through parameter injection. The vulnerability exists due to the application's failure to properly validate or sanitize user-supplied input, particularly in the context of global variable handling within PHP's register_globals feature.
The technical implementation of this vulnerability stems from the dangerous practice of enabling register_globals in PHP applications, which automatically creates global variables from HTTP request parameters. When login.php processes user authentication, it fails to properly validate or sanitize the login_ok parameter, allowing attackers to directly manipulate this variable through HTTP requests. By setting login_ok=1 in the request parameters, attackers can bypass the normal authentication flow and immediately gain administrative access to the system. This represents a critical security flaw that directly violates the principle of least privilege and proper access control enforcement.
The operational impact of this vulnerability is severe and far-reaching, as it allows remote attackers to completely compromise the affected web application without requiring any valid credentials or prior access. Once exploited, the attacker gains full administrative privileges, which can lead to complete system compromise, data exfiltration, unauthorized modifications to system configurations, and potential lateral movement within network environments. The vulnerability affects the authentication mechanism at its core, undermining the fundamental security posture of the application and potentially exposing sensitive data and system resources to unauthorized access.
This vulnerability aligns with CWE-285, which addresses improper authorization issues, and maps to ATT&CK technique T1078 for valid accounts and T1566 for social engineering. The flaw demonstrates poor input validation practices and improper access control implementation that violates industry security standards. Organizations should immediately disable register_globals in their PHP configurations and implement proper input validation and parameter sanitization. Additionally, the application should enforce proper authentication controls and implement robust session management. Regular security audits and code reviews should be conducted to identify similar vulnerabilities in other applications, and the affected system should be patched or updated immediately to prevent exploitation.
The security implications extend beyond immediate unauthorized access, as this vulnerability could enable attackers to establish persistent access through backdoor creation or privilege escalation attacks. The presence of such a flaw in a web application indicates broader security weaknesses in the development lifecycle, including insufficient security testing and inadequate secure coding practices. Organizations should implement comprehensive security measures including network segmentation, intrusion detection systems, and regular vulnerability assessments to prevent exploitation of similar issues. The vulnerability also highlights the importance of following secure coding guidelines and avoiding deprecated PHP features that introduce unnecessary security risks into applications.