Quantum Secular Labs / Blog / Advisories
CVE-2020-29583: Zyxel Multiple Products Use of Hard-Coded Credentials Vulnerability
CVE-2020-29583 is rated critical with a CVSS v3.1 base score of 9.8 and affects Zyxel Multiple Products, along with 30 other products in NVD’s configuration data. Per its scoring, it can be exploited over the network, without authentication, without any user interaction. The scored impact on confidentiality, integrity and availability is the highest available. CISA added it to its Known Exploited Vulnerabilities catalog on 2021-11-03, which means exploitation in the wild has been observed.
Vulnerability 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.
Severity breakdown
CVSS v3.1 9.8: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Attack vector: Network. Exploitable remotely over the network, with no need for local or physical access.
- Attack complexity: Low. No special conditions; the attack can be repeated reliably.
- Privileges required: None. No account or prior access is needed.
- User interaction: None. No action from any user is needed.
- Scope: Unchanged. Impact stays within the vulnerable component.
- Confidentiality impact: High. Total loss of confidentiality; sensitive data can be fully disclosed.
- Integrity impact: High. Total loss of integrity; data or system state can be fully modified.
- Availability impact: High. Total loss of availability; the component can be shut down.
Underlying weakness
CWE-522: Insufficiently Protected Credentials
The product transmits or stores authentication credentials, but it uses an insecure method that is susceptible to unauthorized interception and/or retrieval.
Affected products
- Zyxel Usg20 VPN Firmware: 4.60
- Zyxel Usg20w VPN Firmware: 4.60
- Zyxel Usg40 Firmware: 4.60
- Zyxel Usg40w Firmware: 4.60
- Zyxel Usg60 Firmware: 4.60
- Zyxel Usg60w Firmware: 4.60
- Zyxel Usg110 Firmware: 4.60
- Zyxel Usg210 Firmware: 4.60
- Zyxel Usg310 Firmware: 4.60
- Zyxel Usg1100 Firmware: 4.60
- Zyxel Usg1900 Firmware: 4.60
- Zyxel Usg2200 Firmware: 4.60
- Zyxel Zywall110 Firmware: 4.60
- Zyxel Zywall310 Firmware: 4.60
- Zyxel Zywall1100 Firmware: 4.60
References
- https://www.zyxel.com/support/CVE-2020-29583.shtml
- https://www.zyxel.com/support/security_advisories.shtml
- https://www.eyecontrol.nl/blog/undocumented-user-account-in-zyxel-products.html
- https://www.secpod.com/blog/a-secret-zyxel-firewall-and-ap-controllers-could-allow-for-administrative-access-cve-2020-29583/
- 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.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-29583
- http://ftp.zyxel.com/USG40/firmware/USG40_4.60%28AALA.1%29C0_2.pdf