Source: security@qnapsecurity.com.tw
A NULL pointer dereference 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 launch a denial-of-service (DoS) attack. 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 a Denial-of-Service (DoS) attack due to a NULL pointer dereference. An attacker with administrator privileges can trigger this vulnerability, potentially rendering the device unusable. Immediate patching is crucial to mitigate this risk and prevent service disruption.
Step 1: Administrator Access: The attacker must first obtain administrator-level credentials, possibly through brute-force, phishing, or exploiting another vulnerability. Step 2: Triggering the Vulnerability: Once logged in as an administrator, the attacker executes a specific action or provides crafted input that triggers the vulnerable code path. Step 3: NULL Pointer Dereference: The crafted input or action causes a pointer to become NULL. Step 4: Crash and DoS: The system attempts to dereference the NULL pointer, leading to a crash and denial of service, rendering the NAS device unresponsive.
The vulnerability stems from a NULL pointer dereference within the QNAP operating system. The root cause likely lies in a function that handles user input or system resources. Specifically, a pointer is used without proper validation. If the pointer is unexpectedly NULL (e.g., due to an error condition, missing resource, or crafted input), the code attempts to access the memory location pointed to by the NULL pointer, resulting in a crash and a DoS condition. The lack of input validation or error handling around the pointer dereference allows the attacker to control the execution flow and trigger the crash. The specific function and input vector are not explicitly stated, but the vulnerability is triggered after gaining administrator access, suggesting the flaw lies within a privileged operation or service.
While no specific APTs or malware are directly linked to this CVE, the vulnerability's potential for DoS makes it attractive for threat actors seeking to disrupt operations or extort organizations. The ease of exploitation, once administrator access is obtained, could lead to widespread exploitation. CISA KEV status: Not Applicable at this time, but could be added if active exploitation is observed.
Monitor system logs for unexpected crashes or service restarts, particularly those related to core system processes.
Analyze network traffic for unusual activity originating from the NAS device, especially after administrator login attempts.
Implement intrusion detection systems (IDS) with rules that identify suspicious activity, such as attempts to trigger known vulnerabilities or unusual system calls.
Monitor for failed login attempts, which may indicate attempts to gain administrator access.
Immediately update 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 password policies and multi-factor authentication (MFA) for all administrator accounts.
Regularly audit user accounts and permissions to ensure only authorized users have administrator access.
Implement network segmentation to isolate the NAS device from critical network resources.
Enable automatic security updates to ensure timely patching of future vulnerabilities.
Monitor system logs for suspicious activity and investigate any anomalies promptly.