iOSOperating system · Cisco
CVE-2014-3309
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 NTP implementation in Cisco IOS and IOS XE does not properly support use of the access-group command for a "deny all" configuration, which allows remote attackers to bypass intended restrictions on time synchronization via a standard query, aka Bug ID CSCuj66318.
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 NTP implementation in Cisco IOS and IOS XE fails to properly enforce access-group commands configured with 'deny all,' allowing remote attackers to bypass intended time synchronization restrictions and send standard NTP queries despite access controls being configured.
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
all versions
Ios XeOperating 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
- Low
- Authentication
- None
- Confidentiality
- Partial
- Integrity
- None
- Availability
- None
AV:N/AC:L/Au:N/C:P/I:N/A:N
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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Check if NTP is enabled on the deviceRun command: show ntp status or show ntp associationsAffected if NTP is active and synchronized to a server or peer, indicating the service is running
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Check NTP access-group configurationRun command: show running-config | include ntp access-groupAffected if An NTP access-group is configured with a 'deny all' entry (such as 'ntp access-group peer 99' where ACL 99 contains 'deny any')
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Verify the complete NTP access control configurationRun command: show running-config | include ntp and review any access-list entries related to NTPAffected if The device has an access-list applied to NTP that contains a 'deny all' rule (deny any any) that should block NTP traffic but does not due to this vulnerability
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Confirm device is Cisco IOS or IOS XERun command: show version and review the software version outputAffected if The device runs Cisco IOS or IOS XE (any version), as these are the affected platforms
The device is affected if NTP is enabled AND an NTP access-group with 'deny all' is configured, because the vulnerability allows NTP queries to succeed despite the deny rule.
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 dataConfigure alternative NTP access controls (such as interface-level ACLs or NTP authentication) or upgrade to a Cisco IOS version where Bug ID CSCuj66318 is resolved.
Fix this in iOS
Scoped from the published advisory
- Consultation2.0 h
- Implementation2.0 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 $1,984.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2014-3309 — 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-2014-3309 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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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
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