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Cyber VisionApplication · Cisco

CVE-2022-20685

HIGH · 7.5 CVSS v3.1 Published 2024-11-15
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
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 Modbus preprocessor of the Snort detection engine could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to an integer overflow while processing Modbus traffic. An attacker could exploit this vulnerability by sending crafted Modbus traffic through an affected device. A successful exploit could allow the attacker to cause the Snort process to hang, causing traffic inspection to stop.Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

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

This is an integer overflow vulnerability in Snort's Modbus preprocessor. When processing specially crafted Modbus traffic, an integer overflow occurs that causes the Snort process to hang, resulting in complete traffic inspection failure. An unauthenticated remote attacker can trigger this condition by sending malicious Modbus packets through the affected device.

MitigationApply the Cisco software update that addresses this vulnerability. No workarounds are available, so patching is the only remediation path.

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
Cyber VisionApplication
Affected:= 3.0.0= 3.0.1= 3.0.2= 3.0.3= 3.0.4= 3.0.5= 3.0.6= 3.1.0= 3.1.1= 3.1.2= 3.2.0= 3.2.1
Secure Firewall Threat DefenseApplication
Affected:= 6.2.3= 6.2.3.1= 6.2.3.2= 6.2.3.3= 6.2.3.4= 6.2.3.5= 6.2.3.6= 6.2.3.7= 6.2.3.8= 6.2.3.9= 6.2.3.10= 6.2.3.11
Unified Threat Defense Snort Intrusion Prevention System EngineOperating system
Affected:= 3.17.0s= 3.17.1s= 16.6.1= 16.6.5= 16.6.6= 16.6.7a= 16.6.9= 16.6.10= 16.12.1a= 16.12.2= 16.12.3= 16.12.4

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 the Cisco product running Snort
    Determine whether the environment uses Cisco Cyber Vision, Cisco Firepower Threat Defense, or Cisco Unified Threat Defense Snort IPS Engine
    Affected if The product is any of these three lines and the version matches the affected list
  2. Check the installed version
    Use the system's version reporting command or interface to obtain the exact installed version number
    Affected if The version matches any of: Cyber Vision = 3.0.0 through 3.2.1; Firepower Threat Defense = 6.2.3 through 6.2.3.11; Unified Threat Defense Snort = 3.17.0s, 3.17.1s, 16.6.1, 16.6.5, 16.6.6, 16.6.7a, 16.6.9, 16.6.10, 16.12.1a, 16.12.2, 16.12.3, or 16.12.4
  3. Verify Modbus preprocessor is enabled
    Inspect the Snort configuration file or policy settings to confirm the Modbus preprocessor is active
    Affected if The Modbus preprocessor is enabled and the version is in the affected list above
  4. Check for Modbus traffic inspection
    Review the Snort sensor or Cisco device configuration to determine if Modbus protocol inspection is being performed
    Affected if Modbus traffic inspection is enabled and the Snort version is vulnerable

A user is affected if they are running any of the listed Cisco product versions with the Modbus preprocessor enabled and processing Modbus traffic.

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 the Cisco software update that addresses this vulnerability. No workarounds are available, so patching is the only remediation path.

Fix this in Cyber Vision 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
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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-2022-20685 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