CVE-2008-4932 in U-Mail Webmail server
Summary
by MITRE
webmail/modules/filesystem/edit.php in U-Mail Webmail server 4.91 allows remote attackers to overwrite arbitrary files via an absolute pathname in the path parameter and arbitrary content in the content parameter. NOTE: this can be leveraged for code execution by writing to a file under the web document root.
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Analysis
by VulDB Data Team • 11/09/2024
The vulnerability identified as CVE-2008-4932 resides within the U-Mail Webmail server version 4.91, specifically in the filesystem editing module located at webmail/modules/filesystem/edit.php. This flaw represents a critical path traversal and arbitrary file overwrite vulnerability that enables remote attackers to manipulate the underlying file system through crafted HTTP requests. The vulnerability stems from insufficient input validation and sanitization of user-supplied parameters, particularly the path parameter that accepts absolute file paths and the content parameter that accepts arbitrary data to be written to the targeted file location.
The technical exploitation of this vulnerability occurs when an attacker submits malicious values through the path parameter that specifies an absolute file path on the server filesystem and simultaneously provides content through the content parameter that will be written to that location. The vulnerability lacks proper validation to ensure that the specified path remains within the intended directory boundaries, allowing attackers to traverse the file system and target files outside of the web application's designated directories. This flaw directly maps to CWE-22, known as "Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')", and additionally aligns with CWE-74, "Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')", as the vulnerability enables injection of arbitrary content into targeted files.
The operational impact of this vulnerability is severe and multifaceted, as it provides attackers with the capability to overwrite any file on the server filesystem that the web application process has write permissions for. The most dangerous aspect of this vulnerability is its potential for code execution, as attackers can leverage the file overwrite capability to place malicious code in files located under the web document root. This enables attackers to achieve remote code execution through the web server, potentially leading to full system compromise, data exfiltration, and persistent access. The vulnerability essentially transforms a simple file editing function into a powerful attack vector that can be exploited for privilege escalation and system infiltration.
Security professionals should consider this vulnerability in the context of the MITRE ATT&CK framework, particularly under the T1059.007 technique for "Command and Scripting Interpreter: JavaScript" and T1566.001 for "Phishing: Spearphishing Attachment". The vulnerability can be exploited as part of a broader attack chain where initial access is gained through phishing, followed by exploitation of this file overwrite vulnerability to establish persistent backdoors or web shells. Organizations should implement immediate mitigations including input validation and sanitization of all user-supplied parameters, restriction of web application write permissions to only necessary directories, and implementation of proper path validation to prevent absolute path traversal. Additionally, the use of web application firewalls and regular security audits of web applications can help detect and prevent exploitation attempts of this type of vulnerability.