CVE-2007-0860 in local Calendar System
Summary
by MITRE
** DISPUTED ** Multiple PHP remote file inclusion vulnerabilities in local Calendar System 1.1 allow remote attackers to execute arbitrary PHP code via a URL in the (1) TEMPLATE_DIR parameter to (a) showinvoices.php, (b) showmonth.php, (c) showevents.php, (d) retrieveinvoice.php, (e) modifyitem.php, and (f) lookup_userid.php; or the LIBDIR parameter to (g) editevent.php, (h) resetpassword.php, (i) signup.php, showmonth.php, (j) showday.php, showevents.php, and lookup_userid.php. NOTE: this issue has been disputed by a third party, who states that the associated variables are set in config.php before use.
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Analysis
by VulDB Data Team • 08/07/2024
The vulnerability described in CVE-2007-0860 represents a critical remote file inclusion flaw within the local Calendar System 1.1 web application. This issue manifests as a remote code execution vulnerability that allows attackers to inject and execute arbitrary PHP code on the target server. The vulnerability stems from improper input validation and sanitization of user-supplied parameters that are subsequently used in file inclusion operations. The affected parameters include TEMPLATE_DIR and LIBDIR, which are processed without adequate security controls, creating an attack surface that can be exploited by malicious actors to gain unauthorized access to the underlying system.
The technical exploitation of this vulnerability occurs through manipulation of specific HTTP parameters that are processed by multiple PHP scripts within the calendar system. When attackers supply malicious URLs in the TEMPLATE_DIR parameter to scripts such as showinvoices.php, showmonth.php, showevents.php, retrieveinvoice.php, modifyitem.php, and lookup_userid.php, or through the LIBDIR parameter in scripts like editevent.php, resetpassword.php, signup.php, and several others, the application blindly includes these external resources without proper validation. This behavior directly aligns with CWE-88, which describes improper neutralization of special elements used in an expression, and CWE-94, which covers execution of arbitrary code. The vulnerability is particularly dangerous because it allows attackers to execute code with the privileges of the web server, potentially leading to complete system compromise.
The operational impact of this vulnerability extends beyond simple code execution, as it enables attackers to perform a wide range of malicious activities including data theft, system enumeration, privilege escalation, and persistence mechanisms. Attackers can leverage this vulnerability to upload backdoors, establish command and control channels, or exfiltrate sensitive information from the calendar system. The vulnerability's widespread presence across multiple scripts within the application increases its exploitability and potential damage. According to ATT&CK framework, this vulnerability maps to T1059.007 for execution through PHP and T1021.004 for remote services exploitation. The issue affects the confidentiality, integrity, and availability of the calendar system, potentially leading to unauthorized access to calendar data, user information, and system resources.
The disputed nature of this vulnerability stems from claims that the affected variables are properly set in config.php before use, suggesting that the vulnerability may not exist as described. However, this assertion does not fully address the core issue of insecure parameter handling in the application's file inclusion mechanisms. Even if the variables are defined in configuration files, the lack of proper input validation means that attackers can still manipulate these parameters to include malicious content. The vulnerability remains exploitable through the principle of least privilege violation, where user-supplied input should never be trusted for file inclusion operations. Effective mitigation strategies must focus on implementing proper input validation, using allowlists for acceptable file paths, and employing secure coding practices that prevent dynamic file inclusion based on user input. Organizations should also consider implementing web application firewalls and regular security assessments to detect and remediate similar vulnerabilities in their web applications.
This vulnerability serves as a classic example of how insecure file inclusion practices can lead to severe security consequences in web applications. The flaw demonstrates the importance of proper parameter validation and the dangers of trusting user input for critical system operations. Security practitioners should understand that even if certain variables are initialized in configuration files, the application's handling of user-supplied parameters remains a critical security concern. The vulnerability highlights the need for comprehensive security testing including dynamic analysis and static code review to identify potential remote file inclusion issues. Organizations must prioritize secure coding practices and maintain up-to-date security measures to protect against such exploits. The incident underscores the importance of following security guidelines and standards such as those provided by OWASP and NIST to prevent similar vulnerabilities from being introduced into web applications.