CVE-2017-16651 in Roundcube Webmail
Summary
by MITRE
Roundcube Webmail before 1.1.10, 1.2.x before 1.2.7, and 1.3.x before 1.3.3 allows unauthorized access to arbitrary files on the host's filesystem, including configuration files, as exploited in the wild in November 2017. The attacker must be able to authenticate at the target system with a valid username/password as the attack requires an active session. The issue is related to file-based attachment plugins and _task=settings&_action=upload-display&_from=timezone requests.
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Analysis
by VulDB Data Team • 02/05/2025
This vulnerability in Roundcube Webmail represents a critical path traversal flaw that enables authenticated attackers to access arbitrary files on the host filesystem. The vulnerability affects versions prior to 1.1.10, 1.2.7, and 1.3.3 respectively, and was actively exploited in November 2017. The attack vector specifically targets the file-based attachment plugin functionality within the webmail interface, leveraging the _task=settings&_action=upload-display&_from=timezone request parameters to manipulate file access controls. This flaw operates under the Common Weakness Enumeration category of CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks.
The technical implementation of this vulnerability exploits the lack of proper input validation and sanitization in the file handling mechanisms of Roundcube's settings interface. When users navigate to the timezone settings page and attempt to upload or display attachments, the application fails to properly validate the file paths being accessed. This allows an authenticated user to manipulate the _from parameter to traverse the filesystem and access sensitive files such as configuration files, database credentials, and other system resources that should remain protected. The attack requires a valid user account and active session, making it a privilege escalation vulnerability rather than a purely authentication bypass.
The operational impact of this vulnerability extends beyond simple data theft, as attackers can potentially extract complete system configurations, database connection strings, and other sensitive information that could lead to further compromise of the underlying infrastructure. Configuration files often contain critical system information including database passwords, API keys, and cryptographic secrets that could enable attackers to move laterally within the network. The vulnerability's exploitation in the wild demonstrates its practical value to threat actors, as it provides a straightforward method for information gathering and system reconnaissance without requiring additional attack vectors. According to ATT&CK framework, this represents a technique categorized under T1083 (File and Directory Discovery) and T1552 (Unsecured Credentials) as attackers can use the retrieved information to escalate privileges and access additional system resources.
Organizations using affected Roundcube versions should implement immediate mitigations including upgrading to patched versions, implementing proper input validation for all file operations, and restricting file upload capabilities where possible. Additional protective measures include monitoring for unusual file access patterns, implementing web application firewalls to detect path traversal attempts, and ensuring that file handling operations are performed with minimal required privileges. The vulnerability highlights the importance of proper access controls and input validation in web applications, particularly in components that handle file operations and user-provided data. Security teams should also conduct comprehensive audits of file handling mechanisms across all web applications to identify similar path traversal vulnerabilities that could be exploited in similar fashion.