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:HCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
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, 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
Threat-Actor AttributionAI
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Affected Assets
Mitigating Controls
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 (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.
A.5.10 only requires awareness, a topic-specific acceptable-use policy stating expected behaviours/monitoring, and procedures referencing other controls (e.g. access restrictions, marking, disposal); it performs none of the verb on CWE-522's insecure credential transmission/storage, which requires technical protections like encryption or secure channels that this governance clause does not supply.
A.5.17 mandates secure allocation, transmission, storage, hashing/encryption per 8.24, strong non-reusable passwords, immediate change of defaults/compromise, and no cleartext — directly stopping exploitation of insufficiently protected credentials with only a bounded remainder (e.g. non-password authenticators or post-storage exposure vectors outside its scope).
A.6.2 sets contractual terms, NDAs, and communicates responsibilities to personnel; it has no technical effect on how credentials are protected in transmission or storage and cannot stop exploitation of CWE-522
Regular reminders about password security and personal accountability make users less likely to store or transmit credentials in cleartext or other unprotected forms.
A.8.24's purpose, guidance (b,c), and key management mandate proper cryptography (algorithms, strength, protection of credentials in storage/transmission) per classification, which stops exploitation of insufficiently-protected credentials; remainder is bounded (e.g. non-cryptographic protections like hashing-only or non-crypto obfuscation per CWE-522 details).
A.8.5 mandates MFA, alternative strong methods, no cleartext transmission/storage of passwords, session termination, brute-force protection and secure log-on procedures that directly stop interception/retrieval of credentials even when they exist, leaving only a bounded remainder (e.g. non-password credentials or post-authentication storage outside log-on flows)
Hardening callouts derived
DISA STIG baselines are authored against specific weaknesses. Where this CVE cites a broad weakness class, the mapping is not asserted at that abstraction (owner ruling, 2026-09-25: grade only at Base and below), so no rule is shown here rather than a rule shown against the wrong grain.