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Zyxel security advisory for hardcoded credential vulnerability

CVE: CVE-2020-29583

Summary

Zyxel has released a patch for the hardcoded credential vulnerability of firewalls and AP controllers recently reported by researchers from EYE Netherlands. Users are advised to install the applicable firmware updates for optimal protection.


What is the vulnerability?

A hardcoded credential vulnerability was identified in the “zyfwp” user account in some Zyxel firewalls and AP controllers. The account was designed to deliver automatic firmware updates to connected access points through FTP.


What versions are vulnerable—and what should you do?

After a thorough investigation, we’ve identified the vulnerable products and are releasing firmware patches to address the issue, as shown in the table below. For optimal protection, we urge users to install the applicable updates. For those not listed, they are not affected. Contact your local Zyxel support team if you require further assistance or visit our forum for more information.

Affected product series Patch available in
Firewalls
ATP series running firmware ZLD V4.60 ZLD V4.60 Patch1 in Dec. 2020
USG series running firmware ZLD V4.60 ZLD V4.60 Patch1 in Dec. 2020
USG FLEX series running firmware ZLD V4.60 ZLD V4.60 Patch1 in Dec. 2020
VPN series running firmware ZLD V4.60 ZLD V4.60 Patch1 in Dec. 2020
AP controllers
NXC2500 running firmware V6.00 through V6.10 V6.10 Patch1 on Jan. 8, 2021
NXC5500 running firmware V6.00 through V6.10 V6.10 Patch1 on Jan. 8, 2021

Got a question or a tipoff?

Please contact your local service rep for further information or assistance. If you’ve found a vulnerability, we want to work with you to fix it—contact security@zyxel.com.tw and we’ll get right back to you.


Acknowledgment

Thanks to Niels Teusink at EYE for reporting the issue to us.


Revision history

2020-12-23: Initial release
2020-12-24: Updated the acknowledgement section
2021-01-04: Updated the patch schedule for AP controllers
2021-01-08: Added the forum link