CVE-2005-3820 in vTiger
Summary
by MITRE
Multiple directory traversal vulnerabilities in index.php in vTiger CRM 4.2 and earlier allow remote attackers to read or include arbitrary files, an ultimately execute arbitrary PHP code, via .. (dot dot) and null byte ("%00") sequences in the (1) module parameter and (2) action parameter in the Leads module, as also demonstrated by injecting PHP code into log messages and accessing the log file.
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Analysis
by VulDB Data Team • 06/12/2019
The vulnerability described in CVE-2005-3820 represents a critical directory traversal flaw in vTiger CRM version 4.2 and earlier, exposing the system to remote code execution and arbitrary file access. This vulnerability stems from insufficient input validation in the index.php script where the module and action parameters are processed without proper sanitization. Attackers can exploit this weakness by crafting malicious requests containing .. (dot dot) sequences and null byte encodings to navigate outside the intended directory structure and access restricted files. The vulnerability specifically affects the Leads module where the module and action parameters are directly used in file inclusion operations without adequate security controls.
The technical implementation of this vulnerability follows a classic path of directory traversal exploitation where the application fails to properly validate user-supplied input before using it in file system operations. When the module and action parameters contain sequences such as ../../../etc/passwd or similar path traversal patterns combined with null byte encoding, the application processes these inputs as legitimate file paths. This allows attackers to bypass normal access controls and potentially read system files, include arbitrary PHP files, or even execute malicious code within the context of the web server. The inclusion of null byte sequences adds an additional layer of complexity as it can be used to terminate strings in certain contexts, further complicating the exploitation process.
The operational impact of this vulnerability is severe as it provides attackers with complete control over the affected system. Remote attackers can read sensitive system files including configuration files, database credentials, and other critical information that may lead to further compromise of the entire infrastructure. The ability to include arbitrary PHP files means that attackers can inject malicious code directly into the web application, potentially establishing persistent backdoors, stealing data, or using the compromised system as a launch point for attacks on other systems within the network. The vulnerability also affects log file handling, where PHP code injection into log messages can be executed when the log files are accessed, creating a persistent threat vector that can be exploited even after initial compromise.
This vulnerability aligns with CWE-22 (Improper Limitation of a Pathname to a Restricted Directory) and CWE-74 (Improper Neutralization of Special Elements in Output Used by a Downstream Component) according to the Common Weakness Enumeration standards. The attack pattern follows the MITRE ATT&CK framework's techniques for path traversal and remote code execution, specifically categorized under T1059.007 (Command and Scripting Interpreter: PowerShell) and T1566.001 (Phishing: Spearphishing Attachment) for initial compromise. The vulnerability demonstrates the importance of input validation, proper file access controls, and secure coding practices in web applications. Organizations should implement strict parameter validation, use whitelisting approaches for file operations, and ensure that all user inputs are properly sanitized before being used in file system operations. Additionally, regular security assessments and application firewalls should be deployed to detect and prevent such exploitation attempts.
The exploitation of this vulnerability requires minimal technical expertise and can be accomplished through automated tools, making it particularly dangerous for organizations running unpatched versions of vTiger CRM. The combination of directory traversal with null byte injection creates a multi-layered attack vector that can bypass many traditional security controls. Organizations should immediately apply security patches, implement network segmentation, and monitor for suspicious file access patterns. The vulnerability also highlights the importance of secure configuration management and regular security updates as a fundamental defense mechanism against known exploitation techniques.