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StarosOperating system · Cisco

CVE-2018-0369

HIGH · 8.6 CVSS v3.0 Published 2018-07-16
Fix available
A fix is available. Upgrade to 21.3.15 / 21.5.7 or later.
See remediation →
95/100
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 vulnerability in the reassembly logic for fragmented IPv4 packets of Cisco StarOS running on virtual platforms could allow an unauthenticated, remote attacker to trigger a reload of the npusim process, resulting in a denial of service (DoS) condition. There are four instances of the npusim process running per Service Function (SF) instance, each handling a subset of all traffic flowing across the device. It is possible to trigger a reload of all four instances of the npusim process around the same time. The vulnerability is due to improper handling of fragmented IPv4 packets containing options. An attacker could exploit this vulnerability by sending a malicious IPv4 packet across an affected device. An exploit could allow the attacker to trigger a restart of the npusim process, which will result in all traffic queued toward this instance of the npusim process to be dropped while the process is restarting. The npusim process typically restarts within less than a second. This vulnerability affects: Cisco Virtualized Packet Core-Single Instance (VPC-SI), Cisco Virtualized Packet Core-Distributed Instance (VPC-DI), Cisco Ultra Packet Core (UPC). Cisco Bug IDs: CSCvh29613.

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 vulnerability in Cisco StarOS reassembly logic for fragmented IPv4 packets containing options allows an unauthenticated remote attacker to trigger reloads of the npusim process on virtual platforms. The improper handling of these specially crafted IPv4 fragments can cause all four npusim instances per Service Function to restart simultaneously, resulting in traffic drops during the restart period.

MitigationApply the Cisco patch for bug CSCvh29613 to the affected StarOS installations (VPC-SI, VPC-DI, Ultra Packet Core). As an interim control, consider filtering or rate-limiting fragmented IPv4 packets with options at upstream network devices.

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
StarosOperating system
Affected:>= 21.3, < 21.3.15>= 21.4, < 21.5.7>= 21.6, < 21.6.4

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
None
Integrity
None
Availability
High

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

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

  1. Identify the operating system
    Run 'show version' or check system documentation to confirm the platform is running Cisco StarOS
    Affected if The system is not running Cisco StarOS, then this CVE does not apply
  2. Determine the StarOS version
    Execute 'show version' or 'show system' command to retrieve the installed StarOS version number
    Affected if The version falls within any of these ranges: >= 21.3 and < 21.3.15, OR >= 21.4 and < 21.5.7, OR >= 21.6 and < 21.6.4
  3. Confirm virtual platform deployment
    Run 'show hardware' or 'show system info' to identify if the deployment is VPC-SI, VPC-DI, or Ultra Packet Core (virtual platforms)
    Affected if The system is a physical appliance rather than a virtual platform (the flaw specifically targets npusim on virtual platforms)
  4. Check npusim process status
    Run 'show process npusim' or 'show npu status' to verify if the npusim process is running
    Affected if The npusim process is not present or not running on the system

The system is affected if it runs Cisco StarOS on a virtual platform (VPC-SI, VPC-DI, or Ultra Packet Core) with a version number matching the affected ranges and the npusim process is active.

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
Upgrade available Upgrade to 21.3.15 / 21.5.7 / 21.6.4 or later
Fixed in 21.3.1521.5.721.6.4
Interim mitigation

Apply the Cisco patch for bug CSCvh29613 to the affected StarOS installations (VPC-SI, VPC-DI, Ultra Packet Core). As an interim control, consider filtering or rate-limiting fragmented IPv4 packets with options at upstream network devices.

Fix this in Staros Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,130
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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-2018-0369 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
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  • No spam, self-promotion, credentials, or personal data