dbcve.org
Secure Firewall Threat DefenseApplication · Cisco

CVE-2018-0230

HIGH · 8.6 CVSS v3.0 Published 2018-04-19
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
95/100
Remediation priority · Urgent
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 internal packet-processing functionality of Cisco Firepower Threat Defense (FTD) Software for Cisco Firepower 2100 Series Security Appliances could allow an unauthenticated, remote attacker to cause an affected device to stop processing traffic, resulting in a denial of service (DoS) condition. The vulnerability is due to the affected software improperly validating IP Version 4 (IPv4) and IP Version 6 (IPv6) packets after the software reassembles the packets (following IP Fragmentation). An attacker could exploit this vulnerability by sending a series of malicious, fragmented IPv4 or IPv6 packets to an affected device. A successful exploit could allow the attacker to cause Snort processes on the affected device to hang at 100% CPU utilization, which could cause the device to stop processing traffic and result in a DoS condition until the device is reloaded manually. This vulnerability affects Cisco Firepower Threat Defense (FTD) Software Releases 6.2.1 and 6.2.2, if the software is running on a Cisco Firepower 2100 Series Security Appliance. Cisco Bug IDs: CSCvf91098.

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 Firepower Threat Defense (FTD) Software allows an unauthenticated remote attacker to cause a denial of service by sending malicious fragmented IPv4 or IPv6 packets to affected devices. The improper validation of reassembled packets causes Snort processes to hang at 100% CPU, stopping all traffic processing until manual device reload.

MitigationUpgrade Cisco FTD Software to a version beyond 6.2.2 that includes the fix for this vulnerability. If immediate patching is not possible, consider implementing ingress filtering of fragmented packets 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:= 6.2.1= 6.2.2
Adaptive Security Appliance SoftwareOperating system
Affected:= 9.8\(2\)

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
Changed
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/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 installed product type
    Run 'show version' or check the device型号 to confirm whether the device is running Cisco Firepower Threat Defense (FTD) or Cisco Adaptive Security Appliance (ASA) Software
    Affected if The device is not running FTD or ASA software, the vulnerability does not apply
  2. Check the FTD software version
    Run 'show version' or access the FTD management interface to view the installed FTD version number
    Affected if The installed version is exactly 6.2.1 or 6.2.2
  3. Check the ASA software version
    Run 'show version' on the ASA device to view the installed software version
    Affected if The installed version is exactly 9.8(2)
  4. Verify Snort inspection is enabled
    Check the FTD/ASA configuration for any inspection policies applied to interfaces, particularly examine whether Snort intrusion policies are active using 'show inspection' or reviewing the access-control policy configuration
    Affected if Snort inspection is disabled or no policies are applied, the attack surface is reduced but the device may still be vulnerable if inspection can be triggered
  5. Confirm IPv4/IPv6 traffic processing
    Review the device configuration to confirm that IPv4 and/or IPv6 traffic is being processed and inspected by the device, check interface configurations and service policies
    Affected if The device is not processing IPv4 or IPv6 traffic, the vulnerability cannot be exploited

The environment is affected if the device runs Cisco FTD version 6.2.1 or 6.2.2, or Cisco ASA version 9.8(2), and has Snort inspection enabled for IPv4 or IPv6 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

Upgrade Cisco FTD Software to a version beyond 6.2.2 that includes the fix for this vulnerability. If immediate patching is not possible, consider implementing ingress filtering of fragmented packets at network boundaries to reduce attack surface.

Fix this in Secure Firewall Threat Defense Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,176.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2018-0230 — 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-2018-0230 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