CVE-2020-29583 on CISA KEV

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 p

01What CISA says about this vulnerability

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.

02Required action — verbatim from CISA

Apply updates per vendor instructions.

03Notes & references

• www.zyxel.com — https://www.zyxel.com/support/security_advisories.shtml
• ftp.zyxel.com — http://ftp.zyxel.com/USG40/firmware/USG40_4.60%28AALA.1%29C0_2.pdf
• businessforum.zyxel.com — https://businessforum.zyxel.com/discussion/5254/whats-new-for-zld4-60-patch-1-av…
• businessforum.zyxel.com — https://businessforum.zyxel.com/discussion/5252/zld-v4-60-revoke-and-wk48-firmwa…
• www.eyecontrol.nl — https://www.eyecontrol.nl/blog/undocumented-user-account-in-zyxel-products.html
• www.zyxel.com — https://www.zyxel.com/support/CVE-2020-29583.shtml
• www.secpod.com — https://www.secpod.com/blog/a-secret-zyxel-firewall-and-ap-controllers-could-all…

04SARA's analyst layer — why this matters

This vulnerability is currently on the CISA KEV list, which CISA only adds CVEs to when there is reliable evidence of active exploitation in the wild. For federal civilian agencies, BOD 22-01 requires remediation by the due date above. For everyone else, KEV is the strongest "patch immediately" signal you can get from public threat intel.

05Affected products (summary)

Vendor	Product	Versions
n	a / n/a	n/a

06Detection

Open the Sigma generator with a pre-filled prompt for this CVE to draft a starting detection:

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