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Ubuntu LinuxOperating system · Canonical

CVE-2013-0335

HIGH · 7.6 CVSS v3.1 Published 2013-03-22
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
82/100
Remediation priority · High
Remotely reachable 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
OpenStack Compute (Nova) Grizzly, Folsom (2012.2), and Essex (2012.1) allows remote authenticated users to gain access to a VM in opportunistic circumstances by using the VNC token for a deleted VM that was bound to the same VNC port.

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

In OpenStack Nova, when a VM is deleted, its VNC console token is not properly invalidated. If a new VM is subsequently assigned to the same VNC port, an authenticated attacker who possesses the stale token from the deleted VM can connect to and access the newly deployed VM, bypassing intended access controls.

MitigationImplement proper VNC token invalidation upon VM deletion and ensure token-port binding is validated at connection time, rejecting connections with tokens that do not match the current VM assigned to that port.

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
Ubuntu LinuxOperating system
Affected:= 11.10= 12.04= 12.10
EssexApplication
Affected:= 2012.1
FolsomApplication
Affected:= 2012.2
GrizzlyApplication
Affected:= 2012.2

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
Low
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
High
Availability
Low

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:L

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 Nova version
    Run 'nova-manage version' or check the installed package version (e.g., 'dpkg -l | grep nova' on Ubuntu, or 'rpm -q nova' on RHEL). Compare the version number to the affected ranges: Essex 2012.1, Folsom 2012.2, Grizzly 2012.2, or Ubuntu 11.10/12.04/12.10.
    Affected if The installed Nova version matches one of the affected versions listed in the CVE.
  2. Confirm VNC console is enabled
    Inspect the Nova configuration file (typically /etc/nova/nova.conf) for the 'vnc_enabled' option or presence of VNC-related settings such as 'vncserver_proxyclient_address', 'vncserver_listen', or 'novncproxy_base_url'.
    Affected if VNC console functionality is enabled in the Nova configuration.
  3. Check VNC token configuration
    Review nova.conf for any VNC token-related settings. In vulnerable versions, there is no mechanism to validate that a token is still bound to the intended VM instance. Look for whether the token-to-instance mapping is validated at connection time.
    Affected if The configuration lacks proper token-to-instance binding validation, or you are running an affected version without known fixes.
  4. Verify token invalidation behavior
    Create a test VM, obtain its VNC console token, delete the VM, then attempt to use the original token to connect to a newly created VM assigned the same VNC port. If the connection succeeds, the vulnerability is present.
    Affected if Stale tokens remain valid after VM deletion and can be reused to access different VMs on the same VNC port.

You are affected if you run an affected Nova version (Essex, Folsom, Grizzly or Ubuntu 11.10/12.04/12.10) with VNC console enabled, and the token invalidation fix is not applied.

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Implement proper VNC token invalidation upon VM deletion and ensure token-port binding is validated at connection time, rejecting connections with tokens that do not match the current VM assigned to that port.

Fix this in Ubuntu Linux Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing4.0 h
  • Review / QA2.0 h
15.0 hours of engineering $2,640
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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-2013-0335 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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  • Version or environment caveats, and links to real fixes
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