Adaptive Security Appliance SoftwareOperating system · Cisco
CVE-2013-6696
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 · uneditedCisco Adaptive Security Appliance (ASA) Software does not properly handle errors during the processing of DNS responses, which allows remote attackers to cause a denial of service (device reload) via a malformed response, aka Bug ID CSCuj28861.
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 confidenceCisco ASA Software contains a flaw in its DNS response parsing logic where malformed DNS responses trigger improper error handling, causing the device to reload. A remote attacker can exploit this by sending specially crafted DNS responses to the ASA, resulting in denial of service.
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 versions
Adaptive Security ApplianceHardware / appliance
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
- M
- Authentication
- None
- Confidentiality
- None
- Integrity
- None
- Availability
- Complete
AV:N/AC:M/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 Cisco ASA device is in useIdentify the device model via 'show version' or 'show inventory' command output. This vulnerability only affects Cisco ASA appliances, not other Cisco platforms.Affected if Device is any model of Cisco ASA (5500 series, 5500-X series, ASAv, etc.)
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Verify DNS inspection is enabledRun 'show service-policy' or check the configuration for 'inspect dns' under the policy maps. The vulnerability triggers when the ASA parses DNS responses through its DNS inspection engine.Affected if DNS inspection (inspect dns) is enabled in the active security policy on any interface receiving external DNS traffic
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Check for DNS-related crash reportsRun 'show crashdump' or 'show crashinfo' and review log files for reloads attributed to DNS parsing. Also check 'show log' for messages containing 'DNS' and 'reload' or 'crash'.Affected if Any crash or unexpected reload history linked to DNS inspection processing is found
A Cisco ASA device with DNS inspection enabled on an interface handling external DNS traffic is affected by this vulnerability.
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 the Cisco ASA software update addressing Bug ID CSCuj28861. As a temporary workaround, consider filtering or rate-limiting external DNS responses reaching the ASA if operationally feasible.
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
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2013-6696 — 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-2013-6696 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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- Version or environment caveats, and links to real fixes
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