Source: security@qnapsecurity.com.tw
An out-of-bounds read vulnerability has been reported to affect several QNAP operating system versions. If a remote attacker gains an administrator account, they can then exploit the vulnerability to obtain secret data. We have already fixed the vulnerability in the following versions: QTS 5.2.7.3256 build 20250913 and later QuTS hero h5.2.7.3256 build 20250913 and later QuTS hero h5.3.1.3250 build 20250912 and later
QNAP NAS devices are vulnerable to an out-of-bounds read vulnerability, allowing a remote attacker with administrator privileges to steal sensitive data. Successful exploitation requires prior compromise of an administrator account, but once achieved, the attacker can potentially extract confidential information. This vulnerability underscores the importance of robust access controls and timely patching of QNAP devices.
Step 1: Account Compromise: The attacker must first gain access to a QNAP NAS device with administrator privileges. This could be achieved through various means, such as brute-forcing weak passwords, exploiting other vulnerabilities, or social engineering.
Step 2: Triggering the Vulnerability: Once logged in as an administrator, the attacker crafts a malicious request or input designed to trigger the out-of-bounds read. The specific input depends on the vulnerable function or process.
Step 3: Controlled Read: The crafted input causes the vulnerable function to read beyond the allocated memory buffer. The attacker controls the offset or index used for the read, allowing them to target specific memory locations.
Step 4: Data Exfiltration: The attacker observes the response from the QNAP device. The response contains the contents of the memory locations read, which may include sensitive information such as credentials, configuration data, or other secret data.
Step 5: Repeat and Refine: The attacker may repeat steps 2-4, refining their crafted input to extract more valuable data or to gain further control over the system.
The vulnerability stems from an out-of-bounds read in a QNAP operating system component. The root cause is likely an improper bounds check or lack thereof when accessing data within a memory buffer. Specifically, a function or process responsible for handling certain data structures or network requests fails to validate the index or offset used to read from a buffer. This allows an attacker to supply a crafted input that causes the system to read beyond the allocated memory boundaries. This read operation could expose sensitive information such as configuration files, user credentials, or other secret data residing in memory. The vulnerability is triggered when an authenticated administrator user interacts with a specific function or process, potentially through a network request or file operation. The lack of proper input validation allows the attacker to control the read offset, thereby leaking arbitrary memory contents.
No specific APT groups or malware families are directly linked to this vulnerability at this time. However, the nature of the vulnerability (data exfiltration) makes it attractive to threat actors seeking to steal sensitive information. CISA KEV status: Not Applicable (as of the provided information).
Monitor network traffic for unusual requests or patterns associated with administrator activity, especially those involving file operations or specific QNAP services.
Analyze system logs for suspicious activity, such as unexpected errors, crashes, or attempts to access sensitive files or directories.
Implement file integrity monitoring to detect unauthorized modifications to critical system files.
Monitor for unusual network connections originating from the QNAP device, especially to external IP addresses.
Review administrator account activity logs for any suspicious or unauthorized actions.
Immediately update all affected QNAP devices to the patched versions: QTS 5.2.7.3256 build 20250913 and later, QuTS hero h5.2.7.3256 build 20250913 and later, and QuTS hero h5.3.1.3250 build 20250912 and later.
Enforce strong passwords for all administrator accounts and implement multi-factor authentication (MFA).
Regularly review and audit administrator account access and permissions.
Disable unnecessary services and features on the QNAP devices to reduce the attack surface.
Implement network segmentation to isolate the QNAP devices from other critical network resources.
Regularly back up the QNAP device's data to ensure data recovery in case of a successful attack.
Monitor and review security logs for any suspicious activities.