dbcve.org
Adaptive Security Appliance SoftwareOperating system · Cisco

CVE-2016-6431

HIGH · 7.5 CVSS v3.0 Published 2016-10-27
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 local Certificate Authority (CA) feature of Cisco ASA Software before 9.6(1.5) could allow an unauthenticated, remote attacker to cause a reload of the affected system. The vulnerability is due to improper handling of crafted packets during the enrollment operation. An attacker could exploit this vulnerability by sending a crafted enrollment request to the affected system. An exploit could allow the attacker to cause the reload of the affected system. Note: Only HTTPS packets directed to the Cisco ASA interface, where the local CA is allowing user enrollment, can be used to trigger this vulnerability. This vulnerability affects systems configured in routed firewall mode and in single or multiple context mode.

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 denial-of-service vulnerability in Cisco ASA Software's local Certificate Authority feature allows unauthenticated remote attackers to cause system reload by sending crafted HTTPS enrollment packets. The vulnerability stems from improper handling of these packets during the enrollment operation and affects systems in routed firewall mode with single or multiple context configurations running versions prior to 9.6(1.5).

MitigationUpgrade Cisco ASA Software to version 9.6(1.5) or later. If immediate upgrading is not feasible, disable the local CA feature or restrict access to the enrollment interface to mitigate the risk.

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 SoftwareOperating system
Affected:= 8.0.2.11= 8.0.2.15= 8.0.3= 8.0.3.6= 8.0.3.12= 8.0.3.19= 8.0.4= 8.0.4.3= 8.0.4.9= 8.0.4.16= 8.0.4.23= 8.0.4.25

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:3.0/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 Cisco ASA device and version
    Run 'show version' on the ASA CLI or check through ASDM to retrieve the installed software version
    Affected if The device is running Cisco ASA Software version 8.0.2.11, 8.0.2.15, 8.0.3, 8.0.3.6, 8.0.3.12, 8.0.3.19, 8.0.4, 8.0.4.3, 8.0.4.9, 8.0.4.16, 8.0.4.23, 8.0.4.25, or any version prior to 9.6(1.5)
  2. Verify local CA feature is enabled
    Run 'show run all crypto ca' or 'show crypto ca server' to check if the local Certificate Authority is configured and running
    Affected if The local CA (crypto ca server) feature is enabled and configured on the device
  3. Confirm firewall mode is routed
    Run 'show firewall' or check the mode via 'show run all global | include mode' to determine the operational mode
    Affected if The ASA is operating in routed firewall mode (not transparent mode)
  4. Check context configuration
    Run 'show mode' or 'show context' to see if the device is in single or multiple context mode
    Affected if The device is running in any context mode (single or multiple) with routed firewall mode

The environment is affected if the Cisco ASA is running an affected version (8.0.x versions listed or any version prior to 9.6(1.5)) with the local CA feature enabled in routed firewall mode.

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 ASA Software to version 9.6(1.5) or later. If immediate upgrading is not feasible, disable the local CA feature or restrict access to the enrollment interface to mitigate the risk.

Fix this in Adaptive Security Appliance Software 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-2016-6431 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
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  • No spam, self-promotion, credentials, or personal data