CVE-2018-13338 in TerraMaster TOS
Summary
by MITRE
System command injection in ajaxdata.php in TerraMaster TOS version 3.1.03 allows attackers to execute system commands via the "username" parameter during user creation.
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Analysis
by VulDB Data Team • 04/15/2020
The vulnerability identified as CVE-2018-13338 represents a critical system command injection flaw within TerraMaster TOS version 3.1.03, specifically affecting the ajaxdata.php component during user creation processes. This vulnerability resides in the web application's handling of user input parameters, where the "username" field fails to properly sanitize or validate user-supplied data before incorporating it into system commands. The flaw enables attackers to inject malicious commands that are subsequently executed with the privileges of the web application, potentially leading to complete system compromise. The vulnerability is particularly dangerous because it occurs during legitimate user creation operations, making it difficult to detect and exploit without proper input validation mechanisms in place.
The technical exploitation of this vulnerability follows a classic command injection pattern where attacker-controlled input is concatenated directly into system command execution contexts. When an attacker submits a specially crafted username parameter containing shell metacharacters such as semicolons, ampersands, or command substitution operators, these characters are interpreted by the underlying operating system rather than being treated as literal username characters. This allows for arbitrary command execution, potentially enabling attackers to escalate privileges, access sensitive data, or modify system configurations. The vulnerability maps to CWE-77 in the CWE dictionary, which specifically addresses command injection flaws that occur when user input is directly used in system command execution without proper sanitization or encoding. The attack vector is particularly insidious because it leverages legitimate application functionality, making it harder to distinguish between normal user activity and malicious exploitation attempts.
The operational impact of this vulnerability extends beyond simple command execution to encompass complete system compromise and potential data breaches. Attackers could leverage this vulnerability to gain unauthorized access to the underlying operating system, potentially accessing sensitive files, modifying system configurations, or establishing persistent backdoors. The vulnerability affects all users of TerraMaster TOS version 3.1.03, making it a widespread concern across organizations that rely on this storage management platform. The attack surface is significant since user creation is a common administrative task, and the vulnerability could be exploited by both authenticated and unauthenticated attackers depending on the application's access controls. According to ATT&CK framework, this vulnerability aligns with T1059.001 (Command and Scripting Interpreter: PowerShell) and T1068 (Exploitation for Privilege Escalation) tactics, demonstrating how command injection can serve as a foundational attack vector for broader compromise strategies.
Mitigation strategies for CVE-2018-13338 require immediate implementation of proper input validation and sanitization measures within the application's user creation workflow. The primary defense mechanism involves implementing strict parameter validation that rejects or sanitizes potentially dangerous characters from user input before processing. Organizations should deploy web application firewalls that can detect and block common command injection patterns, particularly those involving semicolons, pipes, and other shell metacharacters. The implementation of principle of least privilege should ensure that the web application executes with minimal necessary permissions, limiting the potential damage from successful exploitation. Additionally, regular security audits and penetration testing should be conducted to identify similar injection vulnerabilities in other application components. The vulnerability highlights the critical importance of input validation in preventing command injection attacks and underscores the need for comprehensive security testing throughout the software development lifecycle. Organizations should also implement monitoring and logging mechanisms to detect suspicious user creation activities that might indicate exploitation attempts, ensuring that any unauthorized command execution is promptly identified and investigated.