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iOSOperating system · Cisco

CVE-2014-2143

MEDIUM · 5.0 CVSS v2.0 Published 2014-04-04
Fix available
A fix is available. Upgrade to after 15.4 or later.
See remediation →
59/100
Remediation priority · Elevated
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
The IKE implementation in Cisco IOS 15.4(1)T and earlier and IOS XE allows remote attackers to cause a denial of service (security-association drop) via crafted Main Mode packets, aka Bug ID CSCun31021.

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 exists in the IKE (Internet Key Exchange) implementation in Cisco IOS 15.4(1)T and earlier versions, as well as IOS XE. Remote attackers can send specially crafted Main Mode IKE packets to cause security associations to be dropped, disrupting IPsec VPN connectivity.

MitigationUpgrade Cisco IOS/IOS XE to a patched version beyond 15.4(1)T. If immediate patching is not feasible, consider restricting IKE traffic (UDP port 500) to trusted sources via ACLs or firewall rules 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
iOSOperating system
Affected:<= 15.4\(1\)t= 15.0= 15.0\(1\)se= 15.1= 15.2= 15.3= 15.3\(2\)s= 15.3\(3\)m= 15.3\(3\)m1= 15.3\(3\)m2= 15.3\(3\)s= 15.3s
Ios XeOperating system
Affected:all versions

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
Authentication
None
Confidentiality
None
Integrity
None
Availability
Partial

AV:N/AC:L/Au:N/C:N/I:N/A:P

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 device platform and OS type
    Run 'show version' and look for 'Cisco IOS' or 'Cisco IOS XE' in the output to determine if the device runs IOS or IOS XE.
    Affected if Device runs Cisco IOS XE (all versions affected) or Cisco IOS version 15.4(1)T or earlier.
  2. Determine the exact IOS version
    Run 'show version' and locate the version number (for example, 15.4(1)T, 15.3(3)M, 15.2(4)E). Compare it against the affected version list.
    Affected if IOS version is any of those listed: <=15.4(1)T, 15.0, 15.0(1)SE, 15.1, 15.2, 15.3, 15.3(2)S, 15.3(3)M, 15.3(3)M1, 15.3(3)M2, 15.3(3)S, or 15.3S.
  3. Verify IKE/IPsec is configured
    Run 'show crypto isakmp sa' to check for active IKE Security Associations, and 'show crypto ipsec sa' for IPsec SAs. Also run 'show running-config | include crypto isakmp' to see if IKE is enabled.
    Affected if IKE is enabled and there are active or configured IPsec VPN tunnels (the vulnerability affects IKE processing for VPN connections).
  4. Check exposure to untrusted IKE traffic
    Run 'show ip interface' or examine ACLs applied to WAN-facing interfaces to determine if UDP port 500 (IKE) is permitted from untrusted sources. Check the interface configuration for any 'crypto map' applied.
    Affected if IKE is exposed to external or untrusted networks (UDP port 500 is allowed inbound on internet-facing interfaces).

The device is affected if it runs Cisco IOS XE (any version) or Cisco IOS version 15.4(1)T or earlier AND has IKE/IPsec configured and exposed to untrusted networks.

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 15.4
Interim mitigation

Upgrade Cisco IOS/IOS XE to a patched version beyond 15.4(1)T. If immediate patching is not feasible, consider restricting IKE traffic (UDP port 500) to trusted sources via ACLs or firewall rules to reduce attack surface.

Fix this in iOS Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
7.0 hours of engineering $1,240
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An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,984.

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-2014-2143 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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