SB2020122410 - Backdoor account in several Zyxel products
Published: December 24, 2020
Security Bulletin ID
SB2020122410
Severity
Critical
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Remote access
Highest impact
Code execution
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 security vulnerability.
1) Use of hard-coded credentials (CVE-ID: CVE-2020-29583)
The vulnerability allows a remote attacker to gain full access to vulnerable system.
The vulnerability exists due to presence of hard-coded account zyfwp with an unchangeable password. A remote unauthenticated attacker can access the affected system via ssh or web interface using the hard-coded credentials and gain administrative privileges.
Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.
Remediation
Install update from vendor's website.
References
- http://ftp.zyxel.com/USG40/firmware/USG40_4.60(AALA.1)C0_2.pdf
- https://businessforum.zyxel.com/discussion/5252/zld-v4-60-revoke-and-wk48-firmware-release
- https://businessforum.zyxel.com/discussion/5254/whats-new-for-zld4-60-patch-1-available-on-dec-15
- https://www.eyecontrol.nl/blog/undocumented-user-account-in-zyxel-products.html
- https://www.zyxel.com/support/CVE-2020-29583.shtml
- https://www.zyxel.com/support/security_advisories.shtml