The web administration interface on ZyXEL NBG-418N devices with firmware 1.00(AADZ.3)C0 has a default password of 1234 for the admin account, which allows remote attackers to obtain administrative privileges by leveraging a LAN session.
Remote attackers can gain complete administrative control of vulnerable ZyXEL NBG-418N routers by exploiting a default password vulnerability. This allows attackers to compromise the network, potentially leading to data breaches, network disruption, and further attacks. The ease of exploitation makes this a high-priority security concern.
Step 1: Network Access: The attacker gains access to the local area network (LAN) where the vulnerable ZyXEL NBG-418N router resides. This could be through physical access, compromised credentials, or other network vulnerabilities. Step 2: Web Interface Access: The attacker accesses the web administration interface of the router, typically via a web browser, by navigating to the router's IP address (e.g., 192.168.1.1). Step 3: Default Credential Authentication: The attacker uses the default administrative credentials: username 'admin' and password '1234'. Step 4: Administrative Privilege Escalation: Upon successful authentication with the default credentials, the attacker gains full administrative privileges, allowing them to modify router settings, view sensitive information, and potentially compromise the entire network.
The vulnerability stems from the use of a hardcoded, default password ('1234') for the administrative account on the web administration interface of ZyXEL NBG-418N routers running firmware version 1.00(AADZ.3)C0. The lack of proper password management and the absence of any security measures to prevent unauthorized access allows attackers to bypass authentication. The root cause is a design flaw where the system does not enforce or prompt for a password change upon initial setup or subsequent access, leaving the default credentials active and accessible. There's no complex technical flaw like a buffer overflow or race condition, but rather a fundamental security misconfiguration.