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OpenstackApplication · Redhat

CVE-2017-2637

CRITICAL · 10.0 CVSS v3.0 Published 2018-07-26
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
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
A design flaw issue was found in the Red Hat OpenStack Platform director use of TripleO to enable libvirtd based live-migration. Libvirtd is deployed by default (by director) listening on 0.0.0.0 (all interfaces) with no-authentication or encryption. Anyone able to make a TCP connection to any compute host IP address, including 127.0.0.1, other loopback interface addresses, or in some cases possibly addresses that have been exposed beyond the management interface, could use this to open a virsh session to the libvirtd instance and gain control of virtual machine instances or possibly take over the host.

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 confidence

A critical design flaw in Red Hat OpenStack Platform director's TripleO deployment configures libvirtd to listen on 0.0.0.0 (all interfaces) without any authentication or encryption. This allows any attacker who can reach the compute host's IP address (including loopback 127.0.0.1 or exposed management interfaces) to connect directly to libvirtd and execute virsh commands, gaining full control of virtual machines or potentially compromising the host.

MitigationRestrict libvirtd to listen only on localhost or management interfaces using libvirtd.conf, enable SASL/TLS authentication, and apply firewall rules to limit access to trusted IPs; alternatively disable the TCP listener if live-migration is not required.

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
OpenstackApplication
Affected:= 7.0= 8= 9= 10

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
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/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. Identify Red Hat OpenStack Platform version
    Run 'cat /etc/redhat-release' or check the overcloudrc file for the OpenStack version, or query the director with 'openstack overcloud status'
    Affected if The version is 7.0, 8, 9, or 10
  2. Locate libvirtd configuration
    Check for /etc/libvirt/libvirtd.conf on the compute nodes deployed via TripleO
    Affected if The file exists and was deployed using TripleO (undercloud/overcloud)
  3. Verify libvirtd TCP listener binding
    Inspect libvirtd.conf for 'listen_addr' or 'listen_address' setting - look for '0.0.0.0' or unset value that defaults to all interfaces
    Affected if listen_addr or listen_address is set to '0.0.0.0' or is commented out (defaulting to all interfaces)
  4. Confirm authentication is disabled
    In libvirtd.conf, check the 'auth_tcp' or 'auth_libvirt' setting - look for 'none' or no SASL/TLS configuration
    Affected if auth_tcp is set to 'none' or no SASL authentication is configured for TCP connections

If running Red Hat OpenStack 7.0-10 and libvirtd.conf shows TCP listening on 0.0.0.0 without authentication, the environment is vulnerable to unauthenticated remote code execution.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Restrict libvirtd to listen only on localhost or management interfaces using libvirtd.conf, enable SASL/TLS authentication, and apply firewall rules to limit access to trusted IPs; alternatively disable the TCP listener if live-migration is not required.

Recommended fix High confidence

Red Hat OpenStack Platform 10 (Mitaka) or later; or errata RHSA-2017:1109

  1. 1. Identify all affected OpenStack director and compute nodes in your environment
  2. 2. Back up all configuration files related to libvirtd and TripleO
  3. 3. Run 'yum update' or 'rpm -q libvirt' to check current libvirt version
  4. 4. Apply the security errata RHSA-2017:1109 which addresses CVE-2017-2637
  5. 5. On all compute nodes, stop the libvirtd service: 'systemctl stop libvirtd'
  6. 6. Configure libvirtd to require authentication by editing /etc/libvirt/libvirtd.conf - set 'listen_tls' to 1 and 'auth_tls' to 'sasl' or 'none' for local connections only
  7. 7. If migration is required, configure TLS certificates for encrypted migration as per Red Hat documentation
  8. 8. Alternatively, restrict libvirtd to listen only on localhost by setting 'listen_address' to '127.0.0.1' in /etc/libvirt/libvirtd.conf
Caveat Enabling authentication for libvirtd may break existing live-migration workflows that rely on unauthenticated access; TLS configuration may be required for migration between hosts

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

Fix this in Openstack Scoped from the published advisory
  • Consultation6.0 h
  • Implementation12.0 h
  • Testing8.0 h
  • Review / QA3.0 h
29.0 hours of engineering $5,100
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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-2017-2637 in production — separate from our analysis above.

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What this is

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What belongs here
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