CVE-2006-2261 in ACal
Summary
by MITRE
PHP remote file inclusion vulnerability in day.php in ACal 2.2.6 allows remote attackers to execute arbitrary PHP code via a URL in the path parameter.
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Analysis
by VulDB Data Team • 06/24/2024
The vulnerability identified as CVE-2006-2261 represents a critical remote file inclusion flaw within the ACal 2.2.6 calendar application, specifically affecting the day.php script. This vulnerability stems from improper input validation and sanitization mechanisms that fail to adequately restrict user-supplied data from being directly incorporated into file inclusion operations. The issue manifests when the application accepts a path parameter that is not properly validated, allowing malicious actors to inject arbitrary URLs that point to remote resources containing malicious PHP code.
The technical exploitation of this vulnerability occurs through a classic remote file inclusion attack vector where an attacker crafts a malicious URL and passes it as the path parameter to the vulnerable day.php script. When the application processes this parameter without proper sanitization, it attempts to include and execute the remote file, effectively allowing the attacker to execute arbitrary PHP code on the target server. This type of vulnerability falls under the CWE-88 category of Improper Neutralization of Argument Delimiters in a Command, specifically manifesting as a remote code execution vector through file inclusion mechanisms. The vulnerability is particularly dangerous because it enables attackers to bypass traditional security controls and directly compromise the underlying server infrastructure.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with persistent access to the affected system. Once exploited, attackers can establish backdoors, escalate privileges, and potentially use the compromised server as a launch point for further attacks within the network. The vulnerability affects the integrity and confidentiality of the entire calendar application, potentially exposing sensitive user data and calendar information. According to ATT&CK framework, this vulnerability maps to T1059.007 for Command and Scripting Interpreter: PHP, and T1505.003 for Server Software Component: Web Shell, indicating the attack paths available to adversaries who successfully exploit this flaw.
Mitigation strategies for CVE-2006-2261 require immediate implementation of input validation and sanitization measures. Organizations should disable the vulnerable remote file inclusion functionality by configuring the PHP setting allow_url_include to off, which prevents the inclusion of remote files. Additionally, all user-supplied input parameters must be strictly validated and sanitized before being processed by the application. The recommended approach involves implementing proper parameter validation techniques such as whitelisting acceptable values, using secure coding practices, and ensuring that all file inclusion operations are performed only with local, validated paths. Regular security audits and vulnerability assessments should be conducted to identify similar issues in other applications, and system administrators should maintain updated versions of all software components to prevent exploitation of known vulnerabilities. The vulnerability also highlights the importance of following secure coding guidelines and implementing defense-in-depth strategies to minimize the attack surface of web applications.