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Vmg3312 B10b FirmwareOperating system · Zyxel

CVE-2018-18754

CRITICAL · 9.8 CVSS v3.0 Published 2018-10-29
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
ZyXEL VMG3312-B10B 1.00(AAPP.7) devices have a backdoor root account with the tTn3+Z@!Sr0O+ password hash in the etc/default.cfg file.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

ZyXEL VMG3312-B10B routers (firmware 1.00(AAPP.7)) contain a hardcoded root account backdoor in the etc/default.cfg file. The account uses the password hash 'tTn3+Z@!Sr0O+', allowing remote attackers to gain full administrative privileges without authentication.

MitigationApply vendor firmware patch when available, or restrict management interface access to trusted networks until patch is released. If device is end-of-life, replace with a supported model.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Vmg3312 B10b FirmwareOperating system
Affected:= 1.00\(aapp.7\)

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify the router model
    Access the router web interface or check the device label to confirm the exact model is VMG3312-B10B
    Affected if Device is a ZyXEL VMG3312-B10B router
  2. Check the firmware version
    Log into the router admin panel and navigate to Status or Maintenance > Firmware version, or use the router's CGI endpoint to retrieve version information
    Affected if Firmware version is 1.00(AAPP.7)
  3. Inspect the configuration file for the backdoor account
    Access the router via FTP, SSH, or Telnet (if enabled) and examine the /etc/default.cfg file for a user entry with username 'root' and password hash 'tTn3+Z@!Sr0O+'
    Affected if The file etc/default.cfg contains a hardcoded root account with password hash tTn3+Z@!Sr0O+
  4. Verify remote management access is enabled
    Check the router's web interface under Network Settings or Administration for Remote Management, TR-069, or WAN access settings
    Affected if Remote management or WAN access is enabled on the device

A user is affected if they have a ZyXEL VMG3312-B10B router running firmware 1.00(AAPP.7) with the hardcoded root backdoor present in etc/default.cfg and remote management access enabled.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply vendor firmware patch when available, or restrict management interface access to trusted networks until patch is released. If device is end-of-life, replace with a supported model.

Fix this in Vmg3312 B10b Firmware Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2018-18754 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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