CVE-2021-35033 : Security Advisory and Response
Discover the impact of CVE-2021-35033 affecting Zyxel routers and WiFi systems. Learn about the vulnerability, affected versions, and mitigation steps to secure your devices.
A vulnerability in specific versions of Zyxel NBG6818, NBG7815, WSQ20, WSQ50, WSQ60, and WSR30 firmware with pre-configured password management could allow an attacker to obtain root access of the device.
Understanding CVE-2021-35033
This CVE affects Zyxel routers and WiFi systems due to a vulnerability in the firmware's pre-configured password management.
What is CVE-2021-35033?
The vulnerability allows attackers to gain root access by connecting a USB-to-UART cable to the device or via enabled remote assistance by an authenticated user.
The Impact of CVE-2021-35033
With a CVSS base score of 7.8, this high-severity vulnerability has a significant impact on confidentiality, integrity, and availability on affected devices.
Technical Details of CVE-2021-35033
The vulnerability is related to a pre-configured password management issue in Zyxel NBG6818, NBG7815, WSQ20, WSQ50, WSQ60, and WSR30 firmware.
Vulnerability Description
The flaw allows attackers to gain root access through physical connection or enabled remote assistance.
Affected Systems and Versions
Zyxel NBG6818 series firmware 1.00(ABSC.0)C0 - 1.00(ABSC.4)C0 Zyxel NBG7815 series firmware 1.00(ABSK.0)C0 - 1.00(ABSK.6)C0 Zyxel WSQ20 series firmware 1.00(ABOF.0)C0 - 1.00(ABOF.10)C0 Zyxel WSQ50 series firmware 1.00(ABKJ.0)C0 - 2.20(ABKJ.6)C0 Zyxel WSQ60 series firmware 1.00(ABND.0)C0 - 2.20(ABND.7)C0 Zyxel WSR30 series firmware 1.00(ABMY.0)C0 - 1.00(ABMY.11)C0
Exploitation Mechanism
Attackers can exploit this vulnerability by physical device dismantling or through enabled remote assistance by authenticated users.
Mitigation and Prevention
To mitigate this vulnerability, update affected Zyxel firmware to the latest versions and follow best security practices.
Immediate Steps to Take
Ensure remote assistance is disabled if not needed and restrict physical access to network devices.
Long-Term Security Practices
Regularly update firmware, change default passwords, and review device configurations and access controls.
Patching and Updates
Refer to Zyxel's security advisory for CVE-2021-35033 and apply recommended patches from the vendor.