CVE-2013-6987 in DiskStation Manager
Summary
by MITRE
Multiple directory traversal vulnerabilities in the FileBrowser components in Synology DiskStation Manager (DSM) before 4.3-3810 Update 3 allow remote attackers to read, write, and delete arbitrary files via a .. (dot dot) in the (1) path parameter to file_delete.cgi or (2) folder_path parameter to file_share.cgi in webapi/FileStation/; (3) dlink parameter to fbdownload/; or unspecified parameters to (4) html5_upload.cgi, (5) file_download.cgi, (6) file_sharing.cgi, (7) file_MVCP.cgi, or (8) file_rename.cgi in webapi/FileStation/.
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Analysis
by VulDB Data Team • 01/15/2025
The vulnerability CVE-2013-6987 represents a critical directory traversal flaw affecting Synology DiskStation Manager versions prior to 4.3-3810 Update 3. This vulnerability resides within the FileBrowser components of the DSM system, specifically targeting multiple CGI scripts that handle file operations through the webapi/FileStation/ interface. The flaw stems from inadequate input validation and sanitization of user-supplied parameters, allowing attackers to manipulate file system paths through maliciously crafted requests containing directory traversal sequences. The vulnerability affects core file management operations including deletion, sharing, downloading, uploading, and renaming functions, making it particularly dangerous for unauthorized file access and manipulation.
The technical exploitation of this vulnerability occurs through the manipulation of specific parameters in various CGI endpoints. Attackers can exploit the vulnerability by injecting .. (dot dot) sequences into path parameters such as path in file_delete.cgi, folder_path in file_share.cgi, and dlink in fbdownload/. Additionally, the vulnerability extends to html5_upload.cgi, file_download.cgi, file_sharing.cgi, file_MVCP.cgi, and file_rename.cgi, all of which accept unspecified parameters that can be manipulated for directory traversal attacks. This multi-vector approach increases the attack surface and makes the vulnerability particularly challenging to defend against completely. The flaw essentially allows attackers to bypass normal file system access controls and navigate to arbitrary directories, potentially accessing sensitive system files, configuration data, or user files that should remain protected.
The operational impact of CVE-2013-6987 is severe and multifaceted, potentially enabling attackers to execute a range of malicious activities including unauthorized file reading, writing, and deletion operations. An attacker could gain access to system-critical files, user documents, or sensitive configuration data, leading to complete system compromise. The vulnerability also enables attackers to manipulate shared folders and potentially spread malicious files throughout the network. According to CWE classification, this vulnerability maps to CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal'), which is a well-documented weakness in file system access controls. The attack pattern aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter and T1078 for Valid Accounts, as attackers could leverage this vulnerability to establish persistent access and execute commands on compromised systems. The vulnerability's impact is further amplified by its presence in multiple CGI endpoints, increasing the probability of successful exploitation.
Mitigation strategies for CVE-2013-6987 require immediate action to update affected Synology DSM systems to version 4.3-3810 Update 3 or later, which contains the necessary patches to address the directory traversal vulnerabilities. Organizations should implement network segmentation to limit access to DSM web interfaces, particularly restricting access to the affected CGI endpoints from untrusted networks. Input validation should be enhanced at all levels, with strict sanitization of all user-supplied parameters before processing file operations. Security monitoring should be implemented to detect suspicious directory traversal attempts, including monitoring for .. sequences in file path parameters. Additionally, organizations should conduct regular security assessments of their file system access controls and ensure that only authorized users have access to file management functions. The vulnerability demonstrates the importance of proper input validation and the principle of least privilege in system design, as these controls could have prevented the exploitation of the directory traversal flaws. Network administrators should also consider implementing web application firewalls to detect and block malicious requests attempting directory traversal attacks against the affected CGI endpoints.