CVE-2017-9328 in TerraMaster TOS
Summary
by MITRE
Shell metacharacter injection vulnerability in /usr/www/include/ajax/GetTest.php in TerraMaster TOS before 3.0.34 leads to remote code execution as root.
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Analysis
by VulDB Data Team • 11/17/2019
The vulnerability identified as CVE-2017-9328 represents a critical shell metacharacter injection flaw within the TerraMaster TOS operating system version 3.0.33 and earlier. This vulnerability exists in the /usr/www/include/ajax/GetTest.php script which processes user input without proper sanitization, creating a pathway for malicious actors to execute arbitrary commands on the affected system with root privileges. The flaw stems from inadequate input validation and improper escaping of special shell characters, allowing attackers to inject malicious commands that are subsequently executed by the system's shell interpreter.
The technical implementation of this vulnerability involves the exploitation of a command injection vector through the web application's AJAX interface. When the GetTest.php script receives user-supplied parameters, it directly incorporates these inputs into shell commands without proper sanitization or escaping mechanisms. This creates a classic shell injection vulnerability that falls under CWE-77, which specifically addresses improper neutralization of special elements used in a command. Attackers can leverage this weakness by crafting malicious input containing shell metacharacters such as semicolons, ampersands, or command substitution operators that are interpreted by the underlying shell, thereby enabling unauthorized command execution.
The operational impact of CVE-2017-9328 is severe and far-reaching, as it grants remote attackers complete system compromise with root-level privileges. This means that unauthorized individuals can execute arbitrary code on the affected TerraMaster devices, potentially leading to full system takeover, data exfiltration, and persistent backdoor installation. The vulnerability affects network-attached storage devices running TerraMaster TOS versions prior to 3.0.34, which are commonly deployed in enterprise and home environments for file sharing and storage solutions. The remote execution capability allows attackers to perform actions such as modifying system configurations, creating new user accounts, accessing sensitive data, and establishing persistent access to the compromised systems.
This vulnerability aligns with several ATT&CK framework techniques including T1059.001 for command and scripting interpreter and T1068 for exploit for privilege escalation. The attack chain typically begins with reconnaissance to identify vulnerable TerraMaster devices, followed by exploitation of the command injection flaw to gain initial access, and concludes with privilege escalation to root level execution. Organizations using affected TerraMaster devices face significant risk of data breaches, system compromise, and potential lateral movement within their networks. The vulnerability demonstrates the critical importance of input validation and secure coding practices in web applications, particularly when dealing with user-supplied data that may be passed to system commands.
Mitigation strategies for CVE-2017-9328 include immediate patching of affected TerraMaster TOS installations to version 3.0.34 or later, which contains the necessary fixes for the command injection vulnerability. System administrators should also implement network segmentation to limit access to affected devices, disable unnecessary services, and monitor for suspicious network activity that may indicate exploitation attempts. Additionally, implementing proper input validation and output encoding in web applications, using parameterized queries where possible, and applying the principle of least privilege can help prevent similar vulnerabilities from occurring in other components of the system architecture. The vulnerability serves as a reminder of the importance of regular security updates and vulnerability assessments in maintaining robust cybersecurity postures.