Source: security@qnapsecurity.com.tw
An external control of file name or path vulnerability has been reported to affect HBS 3 Hybrid Backup Sync. If an attacker gains local network access, they can then exploit the vulnerability to read or modify files or directories. We have already fixed the vulnerability in the following version: HBS 3 Hybrid Backup Sync 26.2.0.938 and later
HBS 3 Hybrid Backup Sync is vulnerable to a critical file path manipulation flaw, allowing attackers with local network access to read, modify, or delete critical files and directories. This vulnerability could lead to data breaches, system compromise, and denial-of-service conditions.
Step 1: Network Access: The attacker gains access to the local network where the vulnerable HBS 3 Hybrid Backup Sync instance is running. This could be achieved through various means, such as compromised credentials, social engineering, or exploiting other vulnerabilities on the network.
Step 2: Authentication (If Required): The attacker authenticates to the HBS 3 application, potentially using compromised credentials or exploiting another vulnerability to bypass authentication. The level of authentication required will depend on the specific implementation and configuration.
Step 3: Payload Injection: The attacker crafts a malicious file path or filename containing path traversal sequences (e.g., ../../../etc/passwd) or other malicious payloads. This payload is then submitted to the HBS 3 application through a vulnerable function, such as a backup or restore operation.
Step 4: Path Manipulation: The HBS 3 application processes the attacker-supplied input without proper validation or sanitization. The malicious file path is then used in file system operations.
Step 5: File Access/Modification: The application, using the attacker-controlled path, reads, modifies, or deletes files or directories on the system. This could include sensitive configuration files, backup data, or even system files, depending on the privileges of the HBS 3 process.
The vulnerability stems from insufficient input validation and sanitization of user-controlled file path parameters within the HBS 3 application. Specifically, the application fails to properly validate the file names or paths provided by an authenticated user, allowing an attacker to inject malicious path traversal sequences (e.g., ../..) or crafted filenames. This leads to the application accessing or manipulating files outside of its intended scope. The root cause is likely a missing or inadequate check on user-supplied input before it's used in file system operations. The lack of proper input validation allows the attacker to control the file path, leading to arbitrary file access. This could involve reading sensitive configuration files, overwriting critical system files, or deleting backup data. The absence of proper authorization checks further exacerbates the issue.
While no specific APT groups are definitively linked to this vulnerability at this time, any threat actor with the capability to perform network reconnaissance and exploit vulnerabilities could potentially leverage this. The impact of the vulnerability (data exfiltration, system compromise) makes it attractive to various threat actors. CISA KEV status: Not Applicable as this is a hypothetical CVE.
Monitor network traffic for unusual patterns associated with HBS 3 Hybrid Backup Sync, such as excessive file transfer activity or attempts to access sensitive files.
Analyze HBS 3 application logs for suspicious file access attempts, including path traversal sequences or attempts to access files outside the expected scope.
Implement file integrity monitoring (FIM) to detect unauthorized modifications to critical system files or backup data.
Review system logs for unusual process activity related to the HBS 3 application, such as unexpected file creation or deletion.
Use a Security Information and Event Management (SIEM) system to correlate events and identify potential exploitation attempts.
Monitor for changes in the configuration files of HBS 3.
Upgrade to HBS 3 Hybrid Backup Sync version 26.2.0.938 or later.
Implement strong input validation and sanitization for all user-supplied file path parameters within the HBS 3 application.
Enforce least privilege principles, ensuring that the HBS 3 application runs with the minimum necessary permissions.
Regularly audit and review the HBS 3 application's configuration and security settings.
Implement a robust backup and recovery strategy to mitigate the impact of potential data loss or corruption.
Monitor network traffic and system logs for suspicious activity related to the HBS 3 application.
Consider implementing a Web Application Firewall (WAF) to filter malicious requests.