Actively exploited · Published Dec 22, 2020 · Assigned by mitre
CVE-2020-29583
Critical 9.8 Exploited
In plain English
A critical-severity security flaw in Multiple Products from Zyxel. Attackers are actively exploiting it in the wild (listed by CISA on November 3, 2021). The chance it is exploited in the next 30 days is estimated at 90.2% (higher than 99.8% of all known vulnerabilities). Ready-made attack tooling exists: Nuclei, public proof-of-concept code. Apply updates per vendor instructions.
CISA guidance
Apply updates per vendor instructions.
Federal agencies must remediate by May 3, 2022.
Official description
Firmware version 4.60 of Zyxel USG devices contains an undocumented account (zyfwp) with an unchangeable password. The password for this account can be found in cleartext in the firmware. This account can be used by someone to login to the ssh server or web interface with admin privileges.
Affected products (as reported)
Weakness: CWE-522 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
References
- https://www.zyxel.com/support/security_advisories.shtml
- http://ftp.zyxel.com/USG40/firmware/USG40_4.60%28AALA.1%29C0_2.pdf
- https://businessforum.zyxel.com/discussion/5254/whats-new-for-zld4-60-patch-1-available-on-dec-15
- https://businessforum.zyxel.com/discussion/5252/zld-v4-60-revoke-and-wk48-firmware-release
- https://www.eyecontrol.nl/blog/undocumented-user-account-in-zyxel-products.html
- https://www.zyxel.com/support/CVE-2020-29583.shtml
- https://www.secpod.com/blog/a-secret-zyxel-firewall-and-ap-controllers-could-allow-for-administrative-access-cve-2020-29583/
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-29583 government-resource