CVE-2006-3684 in PHP Event Calendar
Summary
by MITRE
PHP remote file inclusion vulnerability in calendar.php in SoftComplex PHP Event Calendar 1.4 allows remote attackers to execute arbitrary PHP code via a URL in the path_to_calendar parameter, which overwrites the $path_to_calendar variable from an extract function call.
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Analysis
by VulDB Data Team • 09/18/2017
The vulnerability described in CVE-2006-3684 represents a critical remote file inclusion flaw within the SoftComplex PHP Event Calendar version 1.4 software. This issue stems from improper input validation and unsafe variable handling within the calendar.php script, creating a pathway for malicious actors to execute arbitrary code on vulnerable systems. The vulnerability specifically targets the path_to_calendar parameter which is processed through an extract function call, allowing attackers to manipulate the $path_to_calendar variable and subsequently include remote files.
The technical exploitation of this vulnerability occurs through the extract function which processes user-supplied input without proper sanitization or validation. When a remote attacker provides a malicious URL in the path_to_calendar parameter, the extract function overwrites the $path_to_calendar variable with attacker-controlled data. This creates a remote file inclusion scenario where the application subsequently includes and executes the malicious code from the remote server. The vulnerability directly maps to CWE-94, which describes the weakness of executing arbitrary code or commands, and specifically aligns with CWE-88, concerning the improper neutralization of special elements used in an expression. The flaw demonstrates a classic case of insecure data handling where user input is directly incorporated into the application's execution flow without adequate security controls.
From an operational impact perspective, this vulnerability enables remote code execution capabilities that can result in complete system compromise. Attackers can leverage this flaw to upload and execute malicious scripts, potentially gaining full administrative control over the affected server. The vulnerability affects web applications running the specific version of the PHP Event Calendar software, making it a significant concern for organizations that have not updated their systems. The remote nature of the attack means that exploitation can occur from anywhere on the internet without requiring local access or credentials, making it particularly dangerous for publicly accessible web applications. This vulnerability can also facilitate further attacks within a network by providing a foothold for lateral movement and privilege escalation.
Mitigation strategies for this vulnerability should focus on immediate patching and input validation improvements. Organizations must upgrade to the latest version of the SoftComplex PHP Event Calendar software that addresses this specific flaw. In the interim, administrators should implement strict input validation on all parameters that are later used in dynamic includes or file operations. The extract function should be avoided in security-sensitive contexts or properly sanitized when used. Network-level protections such as web application firewalls can help detect and block malicious requests containing suspicious URL patterns. Additionally, implementing proper access controls and limiting the exposure of vulnerable applications to untrusted networks can reduce the attack surface. The remediation process should also include comprehensive security auditing of similar code patterns throughout the application to identify and fix other potential instances of insecure file handling or remote inclusion vulnerabilities. This vulnerability serves as a reminder of the importance of secure coding practices and the dangers of using functions like extract without proper input validation, aligning with ATT&CK technique T1059.007 for execution through PHP and T1190 for exploitation of remote file inclusion vulnerabilities.