CVE-2020-14031 in NG SMS Gateway
Summary
by MITRE
An issue was discovered in Ozeki NG SMS Gateway through 4.17.6. The outbox functionality of the TXT File module can be used to delete all/most files in a folder. Because the product usually runs as NT AUTHORITY\SYSTEM, the only files that will not be deleted are those currently being run by the system and/or files that have special security attributes (e.g., Windows Defender files).
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Analysis
by VulDB Data Team • 09/23/2020
The vulnerability identified as CVE-2020-14031 represents a critical path traversal and file deletion flaw within the Ozeki NG SMS Gateway version 4.17.6 and earlier. This issue resides within the TXT File module's outbox functionality, which provides users with the ability to manage text file operations. The flaw stems from inadequate input validation and insufficient access control mechanisms that allow unauthorized file operations within the system's file structure. The vulnerability is particularly concerning because the Ozeki NG SMS Gateway typically operates with elevated privileges under the NT AUTHORITY\SYSTEM account, which provides the highest level of system access and permissions. This privileged execution context amplifies the impact of the vulnerability significantly, as the compromised system can potentially delete files across the entire file system hierarchy.
The technical implementation of this vulnerability exploits the lack of proper path validation within the TXT File module's outbox processing. When users interact with the outbox functionality, the system fails to properly sanitize file paths or validate the scope of file operations, allowing malicious users to specify arbitrary file paths that can traverse directories beyond the intended boundaries. This path traversal capability enables attackers to target files in parent directories or system folders, potentially leading to complete system compromise. The vulnerability can be leveraged to delete critical system files, configuration files, or user data, depending on the permissions and access controls in place. The flaw operates at the file system level, bypassing traditional application-level security controls and directly manipulating the underlying operating system's file management capabilities.
The operational impact of CVE-2020-14031 extends far beyond simple file deletion, as it represents a fundamental breakdown in the security model of the SMS gateway system. Given that the application runs with SYSTEM privileges, successful exploitation can result in complete system compromise, data loss, and potential denial of service conditions. The vulnerability affects not only the immediate functionality of the SMS gateway but also poses risks to the broader network infrastructure, as compromised systems often serve as entry points for further attacks. The attacker can selectively target files that are not currently in use, such as those protected by Windows Defender or other security mechanisms, making the attack more sophisticated and harder to detect. This vulnerability aligns with CWE-22 Path Traversal and CWE-770 Allocation of Resources Without Limits or Throttling, as it demonstrates both improper input validation and inadequate resource management. The attack surface is particularly dangerous in environments where the SMS gateway is used for critical communications or serves as part of an enterprise communication infrastructure.
Mitigation strategies for this vulnerability require immediate action including applying the vendor-provided patches or updates that address the path traversal flaw in the TXT File module. Organizations should also implement network segmentation to limit access to the SMS gateway system and restrict the privileges of accounts that interact with the outbox functionality. The principle of least privilege should be enforced by running the application with minimal required permissions rather than SYSTEM privileges whenever possible. Security monitoring should be enhanced to detect unusual file deletion patterns or unauthorized access attempts to system directories. Additionally, regular security audits should be conducted to identify and remediate similar vulnerabilities in other components of the system. Organizations should consider implementing file integrity monitoring solutions to detect unauthorized modifications or deletions of critical system files. The vulnerability also highlights the importance of secure coding practices and input validation, as outlined in the ATT&CK framework's techniques for privilege escalation and defense evasion. Regular security training for administrators and developers is essential to prevent similar issues in future implementations. The affected systems should undergo comprehensive vulnerability assessments to identify other potential paths for exploitation, and access controls should be reviewed and strengthened to prevent unauthorized file system modifications.