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 a user 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 a compromised user account can trigger this vulnerability, potentially rendering the device unavailable. Immediate patching is crucial to mitigate this critical security risk.
Step 1: Account Compromise: An attacker gains access to a valid user account on the QNAP NAS device, potentially through credential stuffing, phishing, or exploiting another vulnerability. Step 2: Triggering the Vulnerability: The attacker, logged in with the compromised account, executes a specific action or series of actions that triggers the vulnerable code path. The exact trigger is unknown from the provided information. Step 3: NULL Pointer Dereference: The triggered code attempts to access memory through a NULL pointer. Step 4: Denial of Service: The NULL pointer dereference causes the QNAP operating system to crash, resulting in a DoS condition, making the device unavailable.
The vulnerability stems from a NULL pointer dereference within the QNAP operating system. The root cause likely involves a function that attempts to access memory through a pointer that has not been properly initialized or has been set to NULL. When the vulnerable code attempts to dereference this NULL pointer, the system attempts to read or write to memory address 0x0, which is an invalid memory location. This leads to a crash and subsequent DoS. The specific function or logic flaw is not detailed in the provided information, but it is triggered after a user account is compromised, indicating the vulnerable code path is likely accessible after authentication. The vulnerability's impact is a DoS, preventing legitimate users from accessing the NAS device's services.
No specific APTs or malware are directly linked to this vulnerability based on the provided information. However, the potential for a DoS attack makes it attractive for various threat actors. This CVE is not listed in the CISA KEV at this time.
Monitor system logs for unexpected crashes or service restarts, especially after user logins.
Analyze network traffic for unusual activity originating from compromised user accounts.
Implement intrusion detection systems (IDS) with rules to detect suspicious activity related to user account actions.
Monitor system resource usage (CPU, memory) for spikes that might indicate a DoS attack.
Examine core dumps or crash reports for evidence of NULL pointer dereferences.
Immediately update QNAP NAS 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 user accounts.
Regularly review user accounts and remove any unused or compromised accounts.
Implement network segmentation to limit the impact of a potential compromise.
Monitor network traffic for suspicious activity and block malicious IP addresses or user agents.
Enable automatic updates to ensure timely patching of future vulnerabilities.
Consider implementing a web application firewall (WAF) to filter malicious traffic.