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 the vulnerability, leading to system unavailability. This vulnerability impacts several QNAP operating system versions, potentially disrupting critical data storage and network services.
Step 1: Credential Acquisition: The attacker must first obtain administrator-level credentials, potentially through phishing, brute-force attacks, or exploiting other vulnerabilities.
Step 2: Triggering the Vulnerability: Once logged in as an administrator, the attacker executes a specific series of commands or actions within the QNAP operating system. The exact sequence is unknown, but it likely involves manipulating specific system configurations or triggering a particular service.
Step 3: NULL Pointer Dereference: The attacker's actions cause a function to be called with a NULL pointer. This pointer is then dereferenced, attempting to access memory at address 0x00000000.
Step 4: Denial of Service: The attempt to access memory at an invalid address results in a system crash or a process termination, leading to a denial-of-service condition. The NAS device becomes unresponsive, and data access is interrupted.
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 without proper validation. Specifically, a pointer is dereferenced without checking if it is NULL. When an attacker, having obtained administrator credentials, triggers a specific sequence of operations, the vulnerable function is called with a NULL pointer, leading to a crash and subsequent DoS. This could be due to improper handling of user-supplied input, leading to a NULL value being assigned to a pointer that is later dereferenced. The specific function and the exact input that triggers the vulnerability are not detailed in the provided information, but the core issue is the lack of a NULL check before dereferencing a pointer.
There is no specific APT or malware known to be exploiting this vulnerability at this time. However, any threat actor targeting NAS devices could potentially leverage this vulnerability, particularly those seeking to disrupt operations or extort victims. This vulnerability is not currently listed in CISA's Known Exploited Vulnerabilities (KEV) catalog.
Monitor system logs for unexpected crashes or service restarts, especially those occurring after administrator login attempts or specific configuration changes.
Analyze crash dumps or core files for evidence of NULL pointer dereferences. Look for stack traces that point to potentially vulnerable functions.
Monitor network traffic for unusual patterns or command sequences that might indicate an attempt to exploit the vulnerability (requires reverse engineering of the trigger).
Implement intrusion detection system (IDS) rules to identify suspicious activity related to administrator account usage and system configuration changes.
Upgrade to the latest patched QNAP operating system 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.
Implement strong password policies and enforce multi-factor authentication (MFA) for administrator accounts.
Regularly review and audit administrator account activity.
Limit administrator access to only the necessary functions and services.
Monitor system logs for suspicious activity and unusual events.
Consider implementing a web application firewall (WAF) to filter malicious requests.
Keep all software and firmware up-to-date to patch any other potential vulnerabilities.