CVE-2020-29583
Exposed Creds in Zyxel Usg20-Vpn Firmware 4.60
Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HSummary
CVE-2020-29583 is a critical-severity Insufficiently Protected Credentials (CWE-522) vulnerability in Zyxel Usg20-Vpn Firmware. Its CVSS base score is 9.8 (Critical).
Operationally, exploitation aligns with the MITRE ATT&CK technique Unsecured Credentials (T1552); ranked in the top 0.2% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog; a public proof-of-concept is referenced.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2020-29583 affects Zyxel USG devices running firmware version 4.60. The vulnerability consists of an undocumented account named zyfwp that uses a fixed, unchangeable password stored in cleartext within the firmware image. This account grants administrative privileges when used to authenticate to either the SSH server or the web management interface.
An attacker with network reachability to an affected device can exploit the issue without any prior credentials or user interaction. By extracting the password from the firmware and logging in as zyfwp, the attacker obtains full administrative control, enabling arbitrary configuration changes, traffic inspection, or further lateral movement. The CVSS 3.1 base score of 9.8 reflects the combination of network attack vector, low complexity, and complete loss of confidentiality, integrity, and availability.
Public references point to Zyxel firmware release notes and independent analyses that discuss the account and subsequent patched releases; practitioners should consult the vendor advisories for specific mitigation steps such as firmware upgrades that remove or disable the account.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2020-21944
Vulnerability Data
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…
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ssh server or web interface with admin privileges.
- CWE(s)
- KEV Date Added
- 03 November 2021
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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- 1 hardening rule · 1 OS baseline
V11.3.3
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Training instructs users on protecting credentials from disclosure or unauthorized access.
Training records for security awareness and role-based training verify education on credential protection practices, tangibly reducing risks from mishandling or exposing credentials.
Protecting authenticator content from unauthorized disclosure and modification while requiring protective controls addresses insufficiently protected credentials.
Rules of behavior include credential protection and non-sharing requirements, reducing exposure of insufficiently protected credentials.
Terminating or revoking credentials stops use of insufficiently protected or lingering credentials post-termination.
Requiring confidentiality/integrity protection for stored credentials directly mitigates insufficiently protected credentials on disk or in configuration stores.
Credentials or keys delivered out-of-band are not exposed to interception or inadequate protection on the main transport.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Encrypting data-at-rest fully prevents insecure credential storage while only partially satisfying the broader data-protection outcome.
Encrypting data-in-transit fully prevents interception of credentials in motion while only partially satisfying the broader data-protection outcome.
Credential management practices directly reduce insecure storage/transmission but do not guarantee encryption or transport protection.
Protecting identity assertions covers conveyance of credentials but is narrower than full credential lifecycle protection.
Authentication policies can enforce stronger credential handling yet address only verification, not storage or transit protection.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Requiring protected storage, transmission, and non-display of passwords prevents credentials from being stored or sent in clear text where they can be harvested by unauthorized actors.
Protecting secret and private keys against disclosure and unauthorized use decreases the exposure of credentials that are stored or transmitted in recoverable form.
Forbidding clear-text transmission and display of passwords, plus the use of stronger alternatives to passwords, prevents credentials from being obtained or reused by attackers.
Acceptable-use expectations that cover protection of credentials and information assets throughout their lifecycle discourage practices that expose or mishandle authentication material.
Contractual clauses that survive termination help ensure that credentials and other secrets are not retained or misused after employment ends.
Regular reminders about password security and personal accountability make users less likely to store or transmit credentials in cleartext or other unprotected forms.