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Adaptive Security Appliance SoftwareApplication · Cisco

CVE-2018-0228

HIGH · 8.6 CVSS v3.1 Published 2018-04-19
Fix available
A fix is available. Upgrade to 6.1.0.6 / 6.2.0.5 or later.
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 ingress flow creation functionality of Cisco Adaptive Security Appliance (ASA) could allow an unauthenticated, remote attacker to cause the CPU to increase upwards of 100% utilization, causing a denial of service (DoS) condition on an affected system. The vulnerability is due to incorrect handling of an internal software lock that could prevent other system processes from getting CPU cycles, causing a high CPU condition. An attacker could exploit this vulnerability by sending a steady stream of malicious IP packets that can cause connections to be created on the targeted device. A successful exploit could allow the attacker to exhaust CPU resources, resulting in a DoS condition during which traffic through the device could be delayed. This vulnerability applies to either IPv4 or IPv6 ingress traffic. This vulnerability affects Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD) Software that is running on the following Cisco products: 3000 Series Industrial Security Appliances (ISA), ASA 5500 Series Adaptive Security Appliances, ASA 5500-X Series Next-Generation Firewalls, ASA Services Module for Cisco Catalyst 6500 Series Switches and Cisco 7600 Series Routers, Adaptive Security Virtual Appliances (ASAv), Firepower 2100 Series Security Appliances, Firepower 4110 Security Appliances, Firepower 9300 ASA Security Modules. Cisco Bug IDs: CSCvf63718.

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 ASA's ingress flow creation functionality allows an unauthenticated remote attacker to cause 100% CPU utilization by sending malicious IP packets that create connections on the targeted device. The root cause is incorrect handling of an internal software lock that prevents other system processes from getting CPU cycles, causing a high CPU condition and DoS. The vulnerability affects both IPv4 and IPv6 traffic.

MitigationApply the vendor patch from Cisco for CSCvf63718 by upgrading to a fixed version of ASA or FTD software. In the interim, consider implementing rate limiting or ACLs to filter suspicious traffic patterns.

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
Adaptive Security Appliance SoftwareApplication
Affected:>= 9.1, < 9.1.7.20>= 9.3, < 9.4.4.13>= 9.5, < 9.6.3.17>= 9.7, < 9.7.1.16>= 9.8, < 9.8.2.14>= 9.2, < 9.2.4.27>= 9.9, < 9.9.1= 98.1\(12.187\)
Secure Firewall Threat DefenseApplication
Affected:>= 6.0, < 6.1.0.6>= 6.2.0, < 6.2.0.5>= 6.2.1, < 6.2.2.2

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:3.1/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. Check Cisco ASA software version
    Log into the ASA CLI and run the command: show version. Look for the version number displayed in the output (typically in the first few lines as 'Cisco ASA Software Version X.X.X').
    Affected if The displayed version falls within any of these ranges: >=9.1 and <9.1.7.20; >=9.3 and <9.4.4.13; >=9.5 and <9.6.3.17; >=9.7 and <9.7.1.16; >=9.8 and <9.8.2.14; >=9.2 and <9.2.4.27; >=9.9 and <9.9.1; or equals 98.1(12.187).
  2. Check Cisco Firepower Threat Defense version
    Log into the FTD CLI (either via SSH or the Firepower Management Center) and run: show version. Identify the FTD version number displayed.
    Affected if The displayed version falls within any of these ranges: >=6.0 and <6.1.0.6; >=6.2.0 and <6.2.0.5; or >=6.2.1 and <6.2.2.2.
  3. Confirm ASA/FTD is processing IP traffic
    Check that the device has active interfaces and is not in a completely idle state. Use 'show interface' to list active interfaces and 'show conn count' to verify active connections exist.
    Affected if The device has active interfaces with IP addresses configured and is accepting or processing network traffic (required for the attack to be triggered).

Your environment is affected if the device runs a Cisco ASA or FTD version within the affected ranges listed above AND the device is actively processing IPv4 or IPv6 traffic on its interfaces.

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 6.1.0.6 / 6.2.0.5 / 6.2.2.2 or later
Fixed in 6.1.0.66.2.0.56.2.2.2
Interim mitigation

Apply the vendor patch from Cisco for CSCvf63718 by upgrading to a fixed version of ASA or FTD software. In the interim, consider implementing rate limiting or ACLs to filter suspicious traffic patterns.

Fix this in Adaptive Security Appliance Software Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
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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-2018-0228 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