dbcve.org
Secure Firewall Threat DefenseApplication · Cisco

CVE-2022-20767

HIGH · 7.5 CVSS v3.1 Published 2022-05-03
Fix available
A fix is available. Upgrade to 7.0.2 or later.
See remediation →
84/100
Remediation priority · High
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 Snort rule evaluation function of Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to improper handling of the DNS reputation enforcement rule. An attacker could exploit this vulnerability by sending crafted UDP packets through an affected device to force a buildup of UDP connections. A successful exploit could allow the attacker to cause traffic that is going through the affected device to be dropped, resulting in a DoS condition. Note: This vulnerability only affects Cisco FTD devices that are running Snort 3.

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 the Snort 3 rule evaluation function of Cisco Firepower Threat Defense allows an unauthenticated remote attacker to cause denial of service by sending crafted UDP packets that exploit improper handling of DNS reputation enforcement rules, forcing UDP connection buildup and causing traffic to be dropped.

MitigationApply the Cisco FTD software update/patch when available; until then, consider filtering or rate-limiting UDP traffic, especially DNS traffic, at network boundaries to reduce attack surface.

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:< 7.0.2= 7.1.0

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
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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 FTD software version
    Log into the Firepower Management Center or use the CLI command 'show version' on the FTD device to retrieve the installed Cisco Firepower Threat Defense version number.
    Affected if The version is less than 7.0.2 or exactly 7.1.0.
  2. Verify Snort 3 is active
    Confirm that the Snort 3 inspection engine is enabled on the affected FTD device. Check via the Firepower Management Center under Policies > Intrusion Policies or use 'show snort3-cpu' in CLI.
    Affected if Snort 3 is the active intrusion detection/prevention engine.
  3. Confirm DNS reputation rules are configured
    Review intrusion policies for any DNS reputation or DNS traffic filtering rules. Access via Firepower Management Center: Policies > Intrusion > Rule Updates or inspect the rule configuration for DNS-related reputation enforcement.
    Affected if DNS reputation enforcement rules or DNS traffic inspection rules are enabled.
  4. Assess UDP traffic exposure
    Determine if the FTD device processes unauthenticated UDP traffic, particularly DNS traffic from external sources. Review access control policies and interface configurations for UDP traffic handling.
    Affected if The device accepts and processes UDP traffic from untrusted networks.

A system is affected if it runs Cisco FTD version 7.1.0 or any version below 7.0.2, has Snort 3 enabled with DNS reputation rules configured, and processes UDP traffic from external or untrusted sources.

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 7.0.2 or later
Fixed in 7.0.2
Interim mitigation

Apply the Cisco FTD software update/patch when available; until then, consider filtering or rate-limiting UDP traffic, especially DNS traffic, at network boundaries to reduce attack surface.

Recommended fix High confidence

Upgrade to FTD version 7.0.2 or later, or 7.1.1 or later

  1. 1. Verify the current FTD software version by logging into the device and running 'show version' command
  2. 2. Confirm Snort 3 is enabled on the device (this vulnerability only affects Snort 3 configurations)
  3. 3. Schedule a maintenance window as the upgrade will require a reload of the device
  4. 4. Download the fixed software version (7.0.2 or later, or 7.1.1 or later) from Cisco's software download center
  5. 5. Upload the new image to the device using 'copy' command or through the management interface
  6. 6. Install the upgrade using 'installations' or the appropriate upgrade procedure for your FTD version
  7. 7. After installation, verify the new version is running with 'show version'
  8. 8. Verify DNS reputation enforcement rules are functioning normally and traffic is flowing as expected
Caveat Upgrading FTD software may require Snort rule reconfiguration; test thoroughly in a staging environment before production deployment

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

Fix this in Secure Firewall Threat Defense Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,130
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,408.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2022-20767 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

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-2022-20767 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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