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FortiwlcApplication · Fortinet

CVE-2017-17540

CRITICAL · 9.8 CVSS v3.0 Published 2018-05-08
Fix available
A fix is available. Upgrade to after 8.3.3 or later.
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
The presence of a hardcoded account in Fortinet FortiWLC 8.3.3 allows attackers to gain unauthorized read/write access via a remote shell.

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 · moderate confidence

Fortinet FortiWLC version 8.3.3 contains a hardcoded backdoor account that provides attackers with unauthorized read/write access through a remote shell, enabling complete compromise of the wireless LAN controller.

MitigationRemove or disable the hardcoded account immediately, apply any available vendor patches, and restrict management interface access to authorized IP ranges while implementing network segmentation.

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
FortiwlcApplication
Affected:>= 7.0, <= 7.0.11>= 8.0, <= 8.3.3

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 FortiWLC system version
    Access the controller's CLI or web interface and retrieve the firmware/software version information using 'show system info' or the equivalent system status command.
    Affected if The reported version falls within 7.0.x (7.0 through 7.0.11) or 8.0.x through 8.3.3.
  2. Locate hardcoded backdoor account
    Review all local user accounts configured on the controller using 'show admin' or equivalent user listing command. Look for any account that was not created by your administrative team.
    Affected if An unrecognized or undocumented administrator account exists on the system.
  3. Verify remote management access settings
    Check the management interface configuration to determine if remote administrative access is enabled, using 'show management' or the equivalent network access settings command.
    Affected if Remote management access is permitted from untrusted networks or broad IP ranges.
  4. Audit account authentication logs
    Review authentication and audit logs for the controller, looking for successful logins from accounts that your team does not recognize or from unexpected IP addresses.
    Affected if Log entries show authentication activity from unknown accounts or suspicious source IPs.

You are affected if your FortiWLC version is between 7.0 and 7.0.11 or between 8.0 and 8.3.3 and an unrecognized administrative account exists on the system.

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.

dbcve · scoped
Upgrade available Upgrade to a release after 8.3.3
Interim mitigation

Remove or disable the hardcoded account immediately, apply any available vendor patches, and restrict management interface access to authorized IP ranges while implementing network segmentation.

Recommended fix Moderate confidence

Latest available FortiWLC version (8.4.x or later, or the most recent release in your supported maintenance branch)

  1. 1. Identify the current FortiWLC version running in your environment using the CLI command: `show version`
  2. 2. If running version 7.0.x (7.0 through 7.0.11) or 8.0.x-8.3.3, this vulnerability is present
  3. 3. Contact Fortinet support or check Fortiguard for the latest available FortiWLC version
  4. 4. Schedule a maintenance window for the upgrade process
  5. 5. Backup the current FortiWLC configuration before upgrading
  6. 6. Upgrade to the latest available FortiWLC version (preferably 8.4.x or later if available)
  7. 7. After upgrade, verify the hardcoded account has been removed by reviewing user accounts: `show system admin`
  8. 8. Change any default passwords that may have been used and ensure strong, unique credentials are in place
Caveat Review Fortinet release notes for the target version to check for configuration changes, deprecated features, or migration requirements between major versions

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Fortiwlc Scoped from the published advisory
  • Consultation4.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
13.0 hours of engineering $2,330
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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-2017-17540 in production — separate from our analysis above.

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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
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data