Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 24 Mar 2022.
iOSOperating system · Cisco

CVE-2017-12233

HIGH · 7.5 CVSS v3.1 Published 2017-09-29
Fix available
A fix is available. Upgrade to after 15.6 or later.
See remediation →
100/100
Remediation priority · Urgent
In the wild 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
Multiple vulnerabilities in the implementation of the Common Industrial Protocol (CIP) feature in Cisco IOS 12.4 through 15.6 could allow an unauthenticated, remote attacker to cause an affected device to reload, resulting in a denial of service (DoS) condition. The vulnerabilities are due to the improper parsing of crafted CIP packets destined to an affected device. An attacker could exploit these vulnerabilities by sending crafted CIP packets to be processed by an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition. Cisco Bug IDs: CSCuz95334.

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

Multiple vulnerabilities in Cisco IOS versions 12.4 through 15.6 allow unauthenticated remote attackers to cause device reloads by sending specially crafted Common Industrial Protocol (CIP) packets. The root cause is improper parsing of CIP packets destined to affected devices, leading to a denial of service condition.

MitigationApply the appropriate Cisco IOS patch for affected versions. If CIP is not required in the environment, consider disabling the CIP feature as a temporary mitigation. Implement network segmentation and access controls to limit exposure to untrusted CIP traffic sources.

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
iOSOperating system
Affected:>= 12.4, <= 15.6

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. Check Cisco IOS version
    Run 'show version' or use 'show running-config | include version' to display the installed IOS version
    Affected if Version falls within 12.4 through 15.6 (inclusive)
  2. Verify CIP feature status
    Use 'show running-config' or check the device configuration for CIP-related settings, or run 'show cip status' if available
    Affected if CIP (Common Industrial Protocol) feature is enabled on the device
  3. Confirm attack surface exposure
    Review network configuration to determine if the device interface accepting CIP traffic is accessible from untrusted networks
    Affected if Device CIP interface is reachable from untrusted or external networks

Affected if the Cisco IOS version is between 12.4 and 15.6 AND the CIP feature is enabled, regardless of network exposure

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 a release after 15.6
Interim mitigation

Apply the appropriate Cisco IOS patch for affected versions. If CIP is not required in the environment, consider disabling the CIP feature as a temporary mitigation. Implement network segmentation and access controls to limit exposure to untrusted CIP traffic sources.

Fix this in iOS Exploited in the wild — priority engagement
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  • Implementation16.0 h
  • Testing8.0 h
  • Review / QA4.0 h
36.0 hours of engineering $6,400
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Scan for this in your stack

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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-2017-12233 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