CVE-2013-4687
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 · uneditedflowd in Juniper Junos 10.4 before 10.4S14, 11.2 and 11.4 before 11.4R6-S2, and 12.1 before 12.1R6 on SRX devices, when certain Application Layer Gateways (ALGs) are enabled, allows remote attackers to cause a denial of service (daemon crash) via crafted TCP packets, aka PRs 727980, 806269, and 835593.
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 confidenceA denial of service vulnerability in the flowd packet forwarding daemon on Juniper SRX devices allows remote attackers to crash the daemon by sending specially crafted TCP packets when certain Application Layer Gateways (ALGs) are enabled. The vulnerability affects multiple Junos releases (10.4 before 10.4S14, 11.2/11.4 before 11.4R6-S2, and 12.1 before 12.1R6) and is exploitable remotely without authentication.
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= 10.4= 11.2= 11.4= 12.1all versionsall versionsall versionsall versionsall versionsall versionsall 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
- None
- Integrity
- None
- Availability
- Complete
AV:N/AC:L/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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Check Junos versionRun 'show version' on the SRX device CLI to identify the installed Junos releaseAffected if Version is 10.4 before 10.4S14, 11.2/11.4 before 11.4R6-S2, or 12.1 before 12.1R6, or if the device is a Srx100, Srx110, Srx1400, Srx210, Srx220, Srx240, or Srx3400 on any version
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Verify flowd daemon is runningRun 'show system processes extensive | match flowd' to confirm the flowd process is activeAffected if flowd is running and the Junos version is in the affected range listed above
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Identify enabled Application Layer GatewaysRun 'show security alg' to list which ALGs are currently enabled on the deviceAffected if Any ALG is enabled (the vulnerability triggers when certain ALGs process specially crafted TCP packets)
A device is affected if it runs a vulnerable Junos version (10.4 before S14, 11.2/11.4 before R6-S2, 12.1 before R6) or is a listed SRX model on any version, and has flowd running with at least one ALG enabled.
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 to version 10.4S14, 11.4R6-S2, or 12.1R6 or later as appropriate for the affected device. If immediate upgrade is not possible, consider disabling unnecessary ALGs as a temporary workaround until the upgrade can be scheduled.
- Consultation2.0 h
- Implementation4.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2013-4687 — 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-2013-4687 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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