CVE-2015-1377 in Webmin
Summary
by MITRE
The Read Mail module in Webmin 1.720 allows local users to read arbitrary files via a symlink attack on an unspecified file.
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Analysis
by VulDB Data Team • 03/09/2019
The vulnerability identified as CVE-2015-1377 resides within the Read Mail module of Webmin version 1.720, representing a critical security flaw that enables local attackers to access sensitive files through a symlink manipulation technique. This vulnerability specifically targets the file handling mechanisms within the web-based system administration tool that is widely deployed for managing Unix and Linux systems through a graphical interface. The issue manifests when the module processes file operations without proper validation of symbolic link references, creating an exploitable path traversal condition that can be leveraged by malicious users with local access privileges.
The technical implementation of this vulnerability stems from inadequate input sanitization and file access controls within the Webmin mail reading functionality. When local users execute the malicious symlink attack, they can manipulate the module's file resolution process to traverse the filesystem and access files that should normally be restricted. This flaw operates through a classic symlink attack vector where the attacker creates or manipulates symbolic links to redirect file access to unintended locations, bypassing normal access controls and privilege boundaries. The vulnerability falls under the category of improper file access control as defined by CWE-284, specifically targeting weak file system permissions and inadequate validation of file references. The attack requires local system access but does not necessitate elevated privileges beyond what is already available to the user, making it particularly dangerous in environments where multiple users share system resources.
The operational impact of CVE-2015-1377 extends beyond simple unauthorized file access, as it can potentially expose sensitive system information including configuration files, authentication credentials, and user data that may lead to further exploitation. Attackers could leverage this vulnerability to read system logs, password files, or application configuration data that contains database connection strings, API keys, or other confidential information. The vulnerability's presence in the Read Mail module suggests that it could be exploited through legitimate administrative functions, potentially evading detection by security monitoring systems that might not flag normal mail reading activities as suspicious. This characteristic aligns with ATT&CK technique T1059.007 for command and scripting interpreter and T1566.001 for spearphishing attachment, as the attack could be concealed within normal system operations and user activities.
Mitigation strategies for CVE-2015-1377 should prioritize immediate patching of the Webmin installation to version 1.730 or later, which contains the necessary fixes for the symlink handling vulnerability. Organizations should implement comprehensive file system access controls and regularly audit symbolic link configurations to prevent unauthorized manipulation. Network segmentation and privilege separation should be enforced to limit local access rights, while monitoring systems should be configured to detect unusual file access patterns that might indicate symlink attack attempts. Additionally, security teams should conduct regular vulnerability assessments and penetration testing to identify similar weaknesses in other system administration tools and applications. The remediation process should also include reviewing and updating access control policies, ensuring that only authorized personnel have local system access, and implementing automated tools to detect and alert on suspicious symbolic link activities. This vulnerability demonstrates the critical importance of proper file system validation and access control mechanisms in web-based administration interfaces, as highlighted by the NIST National Vulnerability Database and common security frameworks that emphasize the need for robust input validation and privilege separation in system management tools.