CVE-2008-4763 in wClient-PHP
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in sample.php in WiKID wClient-PHP 3.0-2 and earlier allow remote attackers to inject arbitrary web script or HTML via the PHP_SELF variable.
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Analysis
by VulDB Data Team • 10/13/2018
The vulnerability identified as CVE-2008-4763 represents a critical cross-site scripting flaw discovered in the WiKID wClient-PHP 3.0-2 and earlier versions. This vulnerability specifically affects the sample.php script within the WiKID authentication system, which is designed for two-factor authentication and secure user access management. The flaw stems from inadequate input validation and output sanitization mechanisms that fail to properly handle user-supplied data within the PHP_SELF variable, creating an exploitable condition that allows malicious actors to inject arbitrary web scripts or HTML content directly into the application's response.
The technical implementation of this vulnerability resides in the improper handling of the PHP_SELF server variable, which contains the filename of the currently executing script. When the sample.php script processes this variable without adequate sanitization, it becomes susceptible to XSS attacks where attackers can embed malicious payloads that execute in the context of other users' browsers. This vulnerability falls under CWE-79 - Improper Neutralization of Input During Web Page Generation, which specifically addresses the failure to properly escape or validate user-controllable input before incorporating it into web page content. The attack vector leverages the fact that the PHP_SELF variable can be manipulated through HTTP request parameters, allowing an attacker to inject script tags or other malicious HTML content that gets rendered in the victim's browser.
The operational impact of this vulnerability extends beyond simple script injection, as it can enable attackers to perform a wide range of malicious activities including session hijacking, credential theft, and redirection to malicious sites. In the context of a two-factor authentication system like WiKID, this vulnerability poses a particularly serious risk since it could allow attackers to compromise the entire authentication process. The vulnerability's exploitation could lead to unauthorized access to protected systems, data breaches, and potential lateral movement within network environments where the WiKID system is deployed. The attack can be executed remotely without requiring any special privileges or authentication, making it especially dangerous in environments where the system is exposed to untrusted users or networks.
Security practitioners should implement multiple layers of mitigation strategies to address this vulnerability effectively. The primary remediation involves implementing strict input validation and output encoding for all user-supplied data, particularly when incorporating values from server variables like PHP_SELF. This includes using proper HTML escaping techniques and implementing Content Security Policy headers to limit the execution of unauthorized scripts. Organizations should also consider implementing the principle of least privilege and ensuring that the affected application runs with minimal required permissions. Additionally, regular security audits and penetration testing should be conducted to identify similar vulnerabilities in other components of the system. The vulnerability demonstrates the critical importance of following secure coding practices and adhering to established security frameworks such as those recommended by the Open Web Application Security Project OWASP, which emphasizes the need for comprehensive input validation and output encoding to prevent XSS attacks. This particular vulnerability aligns with ATT&CK technique T1059.007 - Command and Scripting Interpreter: PowerShell, as it represents a common vector for executing malicious commands through web-based interfaces, and T1566.001 - Phishing: Spearphishing Attachment, as it could be exploited through phishing campaigns targeting the authentication system. Organizations should also consider implementing web application firewalls and intrusion detection systems to monitor for and block suspicious patterns associated with XSS exploitation attempts.