Secure Firewall Threat DefenseApplication · Cisco
CVE-2023-20071
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 · uneditedMultiple Cisco products are affected by a vulnerability in the Snort detection engine that could allow an unauthenticated, remote attacker to bypass the configured policies on an affected system. This vulnerability is due to a flaw in the FTP module of the Snort detection engine. An attacker could exploit this vulnerability by sending crafted FTP traffic through an affected device. A successful exploit could allow the attacker to bypass FTP inspection and deliver a malicious payload.
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 confidenceThis is a policy bypass vulnerability in the Snort detection engine's FTP inspection module. An unauthenticated remote attacker can send specially crafted FTP traffic to bypass configured FTP inspection policies on affected Cisco products, potentially allowing delivery of malicious payloads that would normally be blocked.
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
< 6.4.0.17>= 6.5.0, < 7.0.6>= 7.1.0, < 7.2.4>= 7.3.0, < 7.3.1.2>= 6.7.0, < 7.0.5>= 7.1.0, < 7.1.0.3>= 7.2.0, < 7.2.1
Cyber VisionApplication
< 4.1.3
Unified Threat DefenseApplication
>= 17.3, < 17.3.8>= 17.6, < 17.6.6>= 17.9, < 17.9.4>= 17.11, < 17.11.1a>= 17.12, < 17.12.1a
Meraki Mx Security Appliance FirmwareOperating system
all versionsCVSS 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
- Changed
- Confidentiality
- None
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/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 checksWork through these to decide whether this CVE applies to you.
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Identify the Cisco product running Snort inspectionDetermine if the environment includes Firepower Threat Defense, Cisco Cyber Vision, Unified Threat Defense, or Meraki MX Security ApplianceAffected if The product is any of these four affected product families
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Check the installed product versionUse the product-specific command to display the version (for example, 'show version' on Firepower, or check the Cyber Vision/Unified Threat Defense/Meraki dashboard or CLI for version information)Affected if The version falls into any of these ranges: FTD < 6.4.0.17; >= 6.5.0 and < 7.0.6; >= 7.1.0 and < 7.2.4; >= 7.3.0 and < 7.3.1.2; >= 6.7.0 and < 7.0.5; >= 7.1.0 and < 7.1.0.3; >= 7.2.0 and < 7.2.1. Cyber Vision < 4.1.3. UTD >= 17.3 and < 17.3.8; >= 17.6 and < 17.6.6; >= 17.9 and < 17.9.4; >= 17.11 and
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Confirm FTP inspection policy is configuredLocate the Snort/IPS inspection policy configuration and verify if FTP inspection module or FTP inspection rules are enabled in the security policyAffected if FTP inspection is actively applied to traffic; the vulnerability only affects environments where FTP inspection policies are in use
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Review FTP traffic inspection rulesExamine the inspection policy to see if it processes FTP control channel traffic and whether it enforces policy checks on FTP commandsAffected if The inspection policy processes FTP traffic without additional application-layer validation, allowing the bypass to succeed
The environment is affected if it runs an affected product version AND has FTP inspection policies configured and active, enabling the bypass of Snort's FTP inspection controls.
Generated from the published advisory. Verify against your own configuration.
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 · scoped4.1.36.4.0.177.0.5
Apply Cisco patches or updates for affected products that address the Snort detection engine vulnerability. Review and validate FTP inspection policies to ensure they are functioning correctly after patching.
Secure Firewall Threat Defense: 6.4.0.17, 7.0.6, 7.2.4, or 7.3.1.2 (depending on branch) | Cyber Vision: 4.1.3 | Unified Threat Defense: 17.3.8, 17.6.6, 17.9.4, or 17.11.1a
- Identify the specific Cisco product in use (Secure Firewall Threat Defense, Cyber Vision, Unified Threat Defense, or Meraki Mx Security Appliance)
- Determine the currently installed version using the device management interface or CLI
- For Secure Firewall Threat Defense: Upgrade to 6.4.0.17 or later (6.4.x), 7.0.6 or later (6.5.x-7.0.x), 7.2.4 or later (7.1.x-7.2.x), or 7.3.1.2 or later (7.3.x) depending on your current branch
- For Cyber Vision: Upgrade to version 4.1.3 or later
- For Unified Threat Defense: Upgrade to 17.3.8, 17.6.6, 17.9.4, or 17.11.1a (or later) depending on your current version branch
- For Meraki Mx Security Appliance: Contact Cisco Meraki support for available patches or mitigation options, as no fixed version is currently listed
- After upgrade, verify FTP inspection policies are functioning correctly
- Test that FTP traffic is being properly inspected according to configured policies
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Secure Firewall Threat Defense
Scoped from the published advisory
- Consultation6.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,816.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-20071 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2023-20071 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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