CVE-2013-4392
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 · uneditedsystemd, when updating file permissions, allows local users to change the permissions and SELinux security contexts for arbitrary files via a symlink attack on unspecified files.
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 confidencesystemd contains a symlink attack vulnerability in its file permission update functionality. When systemd updates file permissions, it does not properly validate symlinks, allowing a local attacker to manipulate the permissions and SELinux security contexts of arbitrary files by placing a malicious symlink in the path.
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< 239CVSS 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
- Local
- Complexity
- Low
- Privileges
- Low
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/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 installed systemd versionRun `systemd --version` or `systemctl --version` to identify the systemd version numberAffected if The version displayed is less than 239 (e.g., 238, 237, etc.)
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Identify systemd service files that trigger permission updatesSearch for service files containing ExecStartPost, ExecStartPre, or similar directives that invoke chmod, chown, or systemd's permission update mechanisms. Check /etc/systemd/system/ and /lib/systemd/system/ for custom or third-party servicesAffected if Any service exists that runs permission-changing commands on paths writable by local users
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Audit filesystem paths managed by systemd-tmpfilesExamine /etc/tmpfiles.d/ and /usr/lib/tmpfiles.d/ for entries that manipulate permissions on user-writable directories. Run `ls -la` on directories referenced in tmpfiles.d to check for unexpected symlinksAffected if Any tmpfiles.d configuration modifies permissions in directories where unprivileged users can create symlinks
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Check for existing symlinks in sensitive systemd-managed pathsRun `find /etc -type l -ls` to list all symlinks in /etc, and `find /var -type l -ls` for /var. Verify their targets are expected and not pointing to sensitive filesAffected if Any symlink exists with a target that could be manipulated to alter permissions on files the attacker should not control
A system is affected if systemd version is below 239 AND there exists any service, tmpfiles configuration, or systemd feature that updates file permissions in paths where an attacker can place a malicious symlink.
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 data239
Update systemd to the patched version or apply vendor-supplied security patches. Additionally, restrict local user access to systems where possible.
- Consultation1.0 h
- Implementation2.0 h
- Testing3.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2013-4392 — 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-2013-4392 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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