CVE-2015-8770 in RoundCube
Summary
by MITRE
Directory traversal vulnerability in the set_skin function in program/include/rcmail_output_html.php in Roundcube before 1.0.8 and 1.1.x before 1.1.4 allows remote authenticated users with certain permissions to read arbitrary files or possibly execute arbitrary code via a .. (dot dot) in the _skin parameter to index.php.
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Analysis
by VulDB Data Team • 11/07/2024
The vulnerability identified as CVE-2015-8770 represents a critical directory traversal flaw within the Roundcube webmail application's HTML output module. This security weakness exists in the set_skin function located in program/include/rcmail_output_html.php, affecting versions prior to 1.0.8 and 1.1.x versions before 1.1.4. The flaw enables authenticated attackers with specific privileges to exploit the application's file handling mechanisms and gain unauthorized access to sensitive system resources.
The technical implementation of this vulnerability stems from inadequate input validation within the _skin parameter processing within the index.php script. When an attacker provides a maliciously crafted _skin parameter containing directory traversal sequences such as .. (dot dot), the application fails to properly sanitize or validate this input before using it to construct file paths. This allows the attacker to navigate outside the intended directory structure and access files that should remain restricted, potentially including configuration files, database credentials, or other sensitive data stored on the server.
The operational impact of this vulnerability extends beyond simple file reading capabilities, as the flaw may potentially enable arbitrary code execution depending on the server configuration and the specific files accessed. Attackers with authenticated access and appropriate permissions can leverage this weakness to escalate their privileges, extract confidential information, or potentially compromise the entire webmail application and underlying server infrastructure. The vulnerability particularly affects environments where Roundcube is deployed with default configurations or where user permissions are not properly restricted, creating an attack surface that can be exploited by both internal and external threat actors.
This vulnerability aligns with CWE-22, which categorizes directory traversal attacks as a common weakness in software applications. The flaw also maps to several ATT&CK techniques including T1059 for command and script injection, T1566 for phishing with malicious attachments, and T1213 for data from information repositories. Organizations using vulnerable versions of Roundcube should prioritize immediate patching to address this issue, implementing proper input validation controls, and establishing robust access controls to minimize potential exploitation. Additionally, network segmentation and monitoring of file access patterns can help detect and prevent unauthorized attempts to exploit this directory traversal vulnerability.