Zyxel Multiple Products Use of Hard-Coded Credentials
CVE-2020-29583 is a critical-severity insufficiently protected credentials vulnerability in Usg20-vpn Firmware from Zyxel, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected Usg20-vpn Firmware versions: 4.60. The record does not name a fixed version, so check the vendor advisory. CISA added it to the Known Exploited Vulnerabilities catalogue on November 3, 2021, which means attacks have been observed in the wild.
Attackers are already exploiting this vulnerability, according to CISA.
What to do
- Check which version of Usg20-vpn Firmware you run against the affected versions below, and install the vendor's latest release.
- CISA's required action: Apply updates per vendor instructions.
- Read the advisory on zyxel.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Zyxel | Usg20-vpn Firmware | 4.60 | Not stated |
| Zyxel | Usg20w-vpn Firmware | 4.60 | Not stated |
| Zyxel | Usg40 Firmware | 4.60 | Not stated |
| Zyxel | Usg40w Firmware | 4.60 | Not stated |
| Zyxel | Usg60 Firmware | 4.60 | Not stated |
| Zyxel | Usg60w Firmware | 4.60 | Not stated |
| Zyxel | Usg110 Firmware | 4.60 | Not stated |
| Zyxel | Usg210 Firmware | 4.60 | Not stated |
| Zyxel | Usg310 Firmware | 4.60 | Not stated |
| Zyxel | Usg1100 Firmware | 4.60 | Not stated |
| Zyxel | Usg1900 Firmware | 4.60 | Not stated |
| Zyxel | Usg2200 Firmware | 4.60 | Not stated |
| Zyxel | Zywall110 Firmware | 4.60 | Not stated |
| Zyxel | Zywall310 Firmware | 4.60 | Not stated |
| Zyxel | Zywall1100 Firmware | 4.60 | Not stated |
| Zyxel | Atp100 Firmware | 4.60 | Not stated |
| Zyxel | Atp100w Firmware | 4.60 | Not stated |
| Zyxel | Atp200 Firmware | 4.60 | Not stated |
| Zyxel | Atp500 Firmware | 4.60 | Not stated |
| Zyxel | Atp700 Firmware | 4.60 | Not stated |
| Zyxel | Atp800 Firmware | 4.60 | Not stated |
| Zyxel | Vpn50 Firmware | 4.60 | Not stated |
| Zyxel | Vpn100 Firmware | 4.60 | Not stated |
| Zyxel | Vpn300 Firmware | 4.60 | Not stated |
| Zyxel | Vpn1000 Firmware | 4.60 | Not stated |
Version data comes from NVD's product matching; 5 further products are omitted here. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 9.8 | Critical | NVD |
| CVSS 3.1 | 9.8 | Critical | CISA (ADP) |
| CVSS 2.0 | 10.0 | High | NVD |
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.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: 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.
How developers prevent this class of flaw
- Use an appropriate security mechanism to protect the credentials.
- Make appropriate use of cryptography to protect the credentials.
- Use industry standards to protect the credentials (e.g. LDAP, keystore, etc.).
More Insufficiently Protected Credentials vulnerabilities (CWE-522)
Timeline
- CVE record published.
- Added to CISA's Known Exploited Vulnerabilities catalogue.
- Deadline for US federal agencies to remediate, set by CISA.
- CISA published its SSVC assessment (exploitation: active, automatable: yes, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Third-party and government advisories
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-29583US Government Resource
Technical write-ups (may include proof of concept)
- secpod.com/blog/a-secret-zyxel-firewall-and-ap-controllers-could-allow-for-administrative-access-cve-2020-295…Exploit, Third Party Advisory
Other vulnerabilities in Usg20-vpn Firmware
- 9.8 Critical severity
Zyxel Multiple Firewalls Path Traversal Exploited
- 8.1 High severity
- 7.2 High severity
- 9.8 Critical severity
Zyxel Multiple Firewalls Buffer Overflow Exploited
- 9.8 Critical severity
Zyxel Multiple Firewalls Buffer Overflow Exploited
- 8.8 High severity
Recent Insufficiently Protected Credentials vulnerabilities
- 9.8 Critical severity
Spotted an error? Tell us.