CVE-2017-2342
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 · uneditedMACsec feature on Juniper Networks Junos OS 15.1X49 prior to 15.1X49-D100 on SRX300 series does not report errors when a secure link can not be established. It falls back to an unencrypted link. This can happen when MACsec is configured on ports that are not capable of MACsec or when a secure link can not be established. This can mislead customers into believing that a link is secure. On SRX 300 series devices, prior to 15.1X49-D100, MACsec was only supported on control and fabric ports of SRX340 and SRX345 devices. SRX300 and and SRX320 did not have any MACsec capable ports. Configuring MACsec on ports that were not MACsec capable would have resulted in this issue. Affected releases are Juniper Networks Junos OS 15.1X49 prior to 15.1X49-D100 on SRX300 series.
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 confidenceOn Juniper Junos OS 15.1X49 prior to D100 for SRX300 series, the MACsec feature fails to report errors and silently falls back to unencrypted links when MACsec cannot be established (e.g., on non-MACsec capable ports). This creates a false sense of security since users believe their traffic is encrypted when it is not.
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= 15.1x49CVSS 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
- Adjacent
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- None
CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/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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Confirm device is SRX300 seriesRun 'show chassis hardware' or 'show system information' to identify the device modelAffected if Device model shows SRX300, SRX320, SRX340, SRX345, or other SRX300 series variants
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Check Junos OS versionRun 'show version' to display the installed Junos OS versionAffected if Version shows 15.1X49 (any build prior to D100)
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Verify MACsec is configuredRun 'show configuration | find macsec' or 'show macsec interface' to check if MACsec is enabled on any interfacesAffected if MACsec is configured and enabled on one or more interfaces
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Confirm version is before D100Compare the full version string (e.g., 15.1X49-D90) against 15.1X49-D100Affected if Version build number is less than D100 (e.g., D90, D80, D70, etc.)
Device is affected if it is an SRX300 series running Junos 15.1X49 prior to build D100 with MACsec configured on any interface.
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 dataUpgrade Junos OS on affected SRX300 series devices to version 15.1X49-D100 or later, which properly reports MACsec errors and prevents silent fallback to unencrypted links.
- Consultation4.0 h
- Implementation8.0 h
- Testing4.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2017-2342 — 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-2017-2342 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
- No weaponised exploit code, or anything meant to cause harm
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