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RsyncApplication · Samba

CVE-2017-15994

CRITICAL · 9.8 CVSS v3.0 Published 2017-10-29
Fix available
A fix is available. Upgrade to after 3.1.2 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

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 · unedited
rsync 3.1.3-development before 2017-10-24 mishandles archaic checksums, which makes it easier for remote attackers to bypass intended access restrictions. NOTE: the rsync development branch has significant use beyond the rsync developers, e.g., the code has been copied for use in various GitHub projects.

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 confidence

rsync 3.1.3-development versions before 2017-10-24 improperly process archaic checksum algorithms, allowing remote attackers to circumvent access control mechanisms during file synchronization operations.

MitigationUpgrade rsync to a version released after 2017-10-24. For projects that have incorporated rsync development branch code, identify and patch the checksum handling logic to reject or properly validate archaic checksums.

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
RsyncApplication
Affected:<= 3.1.2

CVSS 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
High
Integrity
High
Availability
High

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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 checks

Work through these to decide whether this CVE applies to you.

  1. Check installed rsync version
    Run 'rsync --version' and note the version number in the output (e.g., rsync 3.1.2 or rsync 3.1.3-development)
    Affected if Version is 3.1.3-development builds dated before October 24, 2017, or version is 3.1.2 or earlier
  2. Identify if this is a Samba Rsync variant
    Run 'rsync --version' and check if the description mentions 'Samba' or check package manager output (e.g., 'dpkg -l | grep rsync' or 'rpm -qi rsync')
    Affected if The installed rsync is the Samba variant and version is 3.1.2 or lower
  3. Check rsync configuration for checksum settings
    Review rsync configuration files (typically /etc/rsyncd.conf, ~/.rsyncd.conf, or command-line arguments) for any 'checksum' or 'csalgo' directives
    Affected if Archaic checksum algorithms (such as MD4 or early MD5 variants) are explicitly configured or the default configuration is being used with a vulnerable version
  4. Verify rsync daemon mode usage
    Check if rsync is running as a daemon (rsyncd) via 'ps aux | grep rsync' or by reviewing /etc/rsyncd.conf existence and configuration
    Affected if Rsync daemon mode is enabled and the version is vulnerable, as remote attackers would interact with the daemon to exploit the checksum bypass

You are affected if your rsync installation is version 3.1.3-development before 2017-10-24 or Samba Rsync version 3.1.2 or earlier, especially when serving files via rsync daemon mode or processing archaic checksums.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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.

dbcve · scoped
Upgrade available Upgrade to a release after 3.1.2
Interim mitigation

Upgrade rsync to a version released after 2017-10-24. For projects that have incorporated rsync development branch code, identify and patch the checksum handling logic to reject or properly validate archaic checksums.

Recommended fix High confidence

rsync 3.1.3 or later stable release

  1. 1. Check current rsync version by running 'rsync --version'
  2. 2. Download rsync 3.1.3 or later stable version from rsync.samba.org or your distribution's package repository
  3. 3. For source compilation: download rsync-3.1.3.tar.gz and run './configure && make && make install'
  4. 4. Alternatively, update via package manager: 'apt-get update && apt-get install rsync' (Debian/Ubuntu) or 'yum install rsync' (RHEL/CentOS)
  5. 5. Verify the upgrade was successful by running 'rsync --version' and confirming the version is 3.1.3 or later

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Rsync Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA2.0 h
20.0 hours of engineering $3,500
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2017-15994 in production — separate from our analysis above.

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What this is

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.

What belongs here
  • 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