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Secure Firewall Threat DefenseApplication · Cisco

CVE-2020-3186

MEDIUM · 5.3 CVSS v3.1 Published 2020-05-06
Fix available
A fix is available. Upgrade to 6.3.0.6 / 6.4.0.7 or later.
See remediation →
62/100
Remediation priority · Elevated
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
A vulnerability in the management access list configuration of Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to bypass a configured management interface access list on an affected system. The vulnerability is due to the configuration of different management access lists, with ports allowed in one access list and denied in another. An attacker could exploit this vulnerability by sending crafted remote management traffic to the local IP address of an affected system. A successful exploit could allow the attacker to bypass the configured management access list policies, and traffic to the management interface would not be properly denied.

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

A vulnerability in Cisco FTD's management access list configuration allows remote attackers to bypass configured access controls. The issue stems from inconsistent port rules across different management access lists—ports allowed in one list but denied in another create bypass opportunities. An attacker sending crafted management traffic to the device's local IP can circumvent intended access restrictions.

MitigationApply Cisco security updates for FTD when available. Review and consolidate all management access list configurations to ensure consistent deny/allow policies across interfaces, removing any conflicting port rules.

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
Secure Firewall Threat DefenseApplication
Affected:>= 6.3.0, < 6.3.0.6>= 6.4.0, < 6.4.0.7>= 6.5.0, < 6.5.0.2
Asa 5505 FirmwareOperating system
Affected:= 9.12\(1.6\)= 201.5\(23.16\)
Asa 5510 FirmwareOperating system
Affected:= 9.12\(1.6\)= 201.5\(23.16\)
Asa 5512 X FirmwareOperating system
Affected:= 9.12\(1.6\)= 201.5\(23.16\)
Asa 5515 X FirmwareOperating system
Affected:= 9.12\(1.6\)= 201.5\(23.16\)
Asa 5520 FirmwareOperating system
Affected:= 9.12\(1.6\)= 201.5\(23.16\)
Asa 5525 X FirmwareOperating system
Affected:= 9.12\(1.6\)= 201.5\(23.16\)
Asa 5540 FirmwareOperating system
Affected:= 9.12\(1.6\)= 201.5\(23.16\)

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
None
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

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 device model and software version
    Run 'show version' or access the device console and execute the version command to obtain the Cisco FTD or ASA firmware version
    Affected if The version falls within these ranges: FTD 6.3.0 to <6.3.0.6, 6.4.0 to <6.4.0.7, 6.5.0 to <6.5.0.2, or ASA firmware 9.12(1.6) or 201.5(23.16)
  2. Locate management access lists
    Execute 'show run access-list' or view the running configuration to identify all access-list entries with management-related purposes or applied to management interfaces
    Affected if Multiple access lists are defined that govern management access to the device
  3. Examine access list rules for port inconsistencies
    Review each management access list entry and compare port allow/deny rules across all lists, noting any ports permitted in one list but denied in another
    Affected if Conflicting port rules exist across different management access lists (e.g., a port allowed in one list but explicitly denied in another applied to the same traffic)
  4. Verify management interface binding
    Run 'show run interface' and 'show access-list' to determine which access lists are bound to which management interfaces (e.g., management0/0)
    Affected if More than one access list is applied to management interfaces or the device has multiple management contexts with separate access lists

The device is vulnerable if it runs an affected version AND has multiple management access lists with inconsistent or conflicting port rules that could allow traffic bypass.

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
Upgrade available Upgrade to 6.3.0.6 / 6.4.0.7 / 6.5.0.2 or later
Fixed in 6.3.0.66.4.0.76.5.0.2
Interim mitigation

Apply Cisco security updates for FTD when available. Review and consolidate all management access list configurations to ensure consistent deny/allow policies across interfaces, removing any conflicting port rules.

Fix this in Secure Firewall Threat Defense Scoped from the published advisory
  • Consultation4.0 h
  • Implementation6.0 h
  • Testing3.0 h
  • Review / QA2.0 h
15.0 hours of engineering $2,690
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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-2020-3186 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
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data