Debian LinuxOperating system · Debian
CVE-2014-0021
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 · uneditedChrony before 1.29.1 has traffic amplification in cmdmon protocol
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 confidenceChrony before version 1.29.1 contains a traffic amplification vulnerability in its cmdmon protocol. An attacker can send small commands to a vulnerable chrony instance which responds with significantly larger responses, enabling reflection/amplification attacks against third parties.
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
Debian LinuxOperating system
= 8.0= 9.0= 10.0
FedoraOperating system
= 19= 20< 1.29CVSS 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
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
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.
-
Verify chrony is installedRun 'rpm -q chrony' on RHEL/Fedora systems or 'dpkg -l chrony' on Debian systems. Alternatively, run 'chronyd --version' to check if the chrony daemon is available.Affected if chrony is installed and running on the system
-
Determine the installed chrony versionRun 'chronyd --version' or check the package version with 'rpm -q chrony' (RHEL/Fedora) or 'dpkg -s chrony' (Debian). Compare the version number to the affected range of versions before 1.29.Affected if The installed version is chrony version 1.29 or earlier, or the specific Debian/Fedora versions listed (Debian 8.0, 9.0, 10.0; Fedora 19, 20)
-
Check if cmdmon protocol is enabled and accessibleExamine the chrony configuration file (typically /etc/chrony/chrony.conf or /etc/chronyd.conf) for directives that enable cmdmon/network access, such as 'cmdallow' or 'cmdport'. Also check if chrony is bound to a network interface by reviewing running processes or netstat/ss output for port 323.Affected if The cmdmon interface is enabled and accessible, allowing remote commands to be sent to the chronyd service
-
Verify network exposure of the cmdmon serviceRun 'ss -ulnp | grep 323' or 'netstat -ulnp | grep 323' to check if chrony is listening on port 323 (the default cmdmon port). Determine if the service is bound to 0.0.0.0 (all interfaces) or a specific IP, and whether firewall rules permit external access.Affected if Chrony cmdmon is listening on a network interface accessible from untrusted networks, enabling external attackers to send amplification commands
The system is affected if chrony version 1.29 or earlier is installed AND the cmdmon protocol is enabled and network-accessible, allowing external parties to trigger amplified traffic responses.
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 data1.29
Upgrade chrony to version 1.29.1 or later. If upgrading is not immediately feasible, disable or restrict access to the cmdmon protocol through firewall rules or network segmentation.
Fix this in Debian Linux
Scoped from the published advisory
- Consultation1.0 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 $1,664.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2014-0021 — 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-2014-0021 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
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
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
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data