CVE-2015-6912 in Video Station
Summary
by MITRE
Synology Video Station before 1.5-0763 allows remote attackers to execute arbitrary shell commands via shell metacharacters in the subtitle_codepage parameter to subtitle.cgi.
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Analysis
by VulDB Data Team • 07/07/2024
The vulnerability identified as CVE-2015-6912 affects Synology Video Station versions prior to 1.5-0763, presenting a critical remote code execution risk through improper input validation in the subtitle.cgi script. This flaw resides in the subtitle_codepage parameter handling where the application fails to properly sanitize user-supplied input before incorporating it into shell commands. The vulnerability stems from a classic command injection flaw that allows attackers to inject malicious shell metacharacters into the parameter, thereby enabling arbitrary command execution on the underlying operating system. Such a vulnerability represents a severe security weakness that directly violates the principle of least privilege and input sanitization, creating an attack surface that could be exploited by remote adversaries without authentication requirements.
The technical exploitation of this vulnerability occurs when an attacker crafts a malicious request to the subtitle.cgi endpoint with a specially crafted subtitle_codepage parameter containing shell metacharacters such as semicolons, ampersands, or backticks. These metacharacters are interpreted by the shell and executed with the privileges of the web server process, typically running as a privileged user such as root or a dedicated web service account. The vulnerability maps directly to CWE-77 and CWE-94, which classify it as a command injection flaw and a code injection vulnerability respectively. From an attack framework perspective, this vulnerability aligns with ATT&CK technique T1059.001 for command and scripting interpreter, specifically shell scripting, and T1068 for exploit for privilege escalation through the execution of arbitrary code on the target system.
The operational impact of CVE-2015-6912 extends beyond simple remote code execution, as it provides attackers with full control over the affected Synology device and its underlying file system. Attackers could potentially access, modify, or delete sensitive media files, exfiltrate user data, install malware, or use the compromised system as a pivot point for further attacks within the network. The vulnerability affects not just individual media files but potentially the entire network storage infrastructure, as Synology devices often serve as central repositories for corporate and personal data. The lack of authentication requirements for exploitation means that any remote attacker can leverage this vulnerability, making it particularly dangerous for devices accessible over the internet. Organizations using affected versions of Synology Video Station face significant risk of data breaches, system compromise, and potential regulatory violations, especially in environments where strict compliance with data protection standards is required.
Mitigation strategies for this vulnerability require immediate patching of the affected Synology Video Station software to version 1.5-0763 or later, which incorporates proper input validation and sanitization measures. System administrators should also implement network segmentation to limit access to Synology devices, deploy web application firewalls to monitor and filter suspicious requests, and conduct regular security audits of installed applications. The vulnerability highlights the importance of input validation practices and the need for secure coding standards in web applications, particularly in handling user-supplied data that may be passed to system commands. Organizations should also consider implementing principle of least privilege for web applications, ensuring that web server processes operate with minimal required privileges to reduce the potential impact of successful exploitation. Additionally, regular security updates and vulnerability assessments should be part of the overall security posture to prevent similar issues from occurring in other applications and services within the organization's infrastructure.