Adaptive Security Appliance SoftwareOperating system · Cisco
CVE-2013-5544
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 · uneditedThe VPN authentication functionality in Cisco Adaptive Security Appliance (ASA) Software allows remote attackers to cause a denial of service (device reload) by sending many username-from-cert IKE requests, aka Bug ID CSCua91108.
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 · moderate confidenceThe vulnerability exists in Cisco ASA Software's VPN authentication functionality where processing IKE requests with the username-from-cert option can trigger a device reload when sent in rapid succession. This represents a denial-of-service condition where an attacker can cause the ASA appliance to crash and restart remotely by sending specially crafted certificate-based VPN authentication requests.
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
all versionsCVSS 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
- High
- Authentication
- None
- Confidentiality
- None
- Integrity
- None
- Availability
- Complete
AV:N/AC:H/Au:N/C:N/I:N/A:C
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 checksWork through these to decide whether this CVE applies to you.
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Confirm device is Cisco ASARun 'show version' and verify the device model is Cisco Adaptive Security Appliance (ASA)Affected if Device is a Cisco ASA appliance
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Verify IKE/IPSec VPN is configuredRun 'show run crypto isakmp' or 'show run all crypto isakmp' to check if IKE (ISAKMP) is enabledAffected if IKE is enabled and VPN is configured
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Check for username-from-cert option in IKE policyRun 'show run all crypto isakmp policy | include username-from-cert' or inspect the IKEv1/IKEv2 group configuration for the username-from-cert keywordAffected if The username-from-cert option is present in the IKE or group configuration
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Identify the ASA software versionRun 'show version' and note the full software version stringAffected if Any version of Cisco ASA Software is listed (all versions are affected)
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Review device for unexpected reloads or crashinfoRun 'show reload' and 'show crashinfo' (or 'show tech-support' if available) to look for recent reloads with IKE/ISAKMP related reasonsAffected if Device has recently reloaded with IKE, ISAKMP, or VPN authentication as the recorded cause
The user is affected if they have a Cisco ASA with IKE VPN enabled and the username-from-cert option configured in their IKE authentication settings.
Generated from the published advisory. Verify against your own configuration.
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 dataApply rate limiting to IKE authentication requests on the ASA interface and consider upgrading to a patched ASA software version if available. Additionally, implement ingress traffic filtering to limit suspicious VPN authentication patterns.
Fix this in Adaptive Security Appliance Software
Scoped from the published advisory
- Consultation2.0 h
- Implementation3.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,272.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2013-5544 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2013-5544 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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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.
- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
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