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StarosOperating system · Cisco

CVE-2018-0273

MEDIUM · 5.3 CVSS v3.0 Published 2018-04-19
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
62/100
Remediation priority · Elevated
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 IPsec Manager of Cisco StarOS for Cisco Aggregation Services Router (ASR) 5000 Series Routers and Virtualized Packet Core (VPC) System Software could allow an unauthenticated, remote attacker to terminate all active IPsec VPN tunnels and prevent new tunnels from being established, resulting in a denial of service (DoS) condition. The vulnerability is due to improper processing of corrupted Internet Key Exchange Version 2 (IKEv2) messages. An attacker could exploit this vulnerability by sending crafted IKEv2 messages toward an affected router. A successful exploit could allow the attacker to cause the ipsecmgr service to reload. A reload of this service could cause all IPsec VPN tunnels to be terminated and prevent new tunnels from being established until the service has restarted, resulting in a DoS condition. This vulnerability affects the following Cisco products when they are running Cisco StarOS: Cisco Aggregation Services Router (ASR) 5000 Series Routers, Virtualized Packet Core (VPC) System Software. Cisco Bug IDs: CSCve29605.

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

The vulnerability exists in the IPsec Manager component of Cisco StarOS running on ASR 5000 Series Routers and Virtualized Packet Core systems. When malformed or corrupted Internet Key Exchange Version 2 (IKEv2) messages are processed, the ipsecmgr service fails to handle them properly and triggers a reload. This service reload terminates all active IPsec VPN tunnels immediately and blocks new tunnel establishment until the service fully restarts, resulting in denial of service.

MitigationApply the Cisco patch for bug CSCve29605 by upgrading to a fixed StarOS version. Schedule a maintenance window to minimize disruption, as the IPsec service will be impacted during the upgrade.

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:= 19.4.2.65120= 19.6.0= 21.2.0= 21.2.6= 21.4.0

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
None
Integrity
None
Availability
Low

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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 the platform running Cisco StarOS
    Confirm the system is either an ASR 5000 Series Router or a Virtualized Packet Core (VPC) system by checking the hardware model or virtual machine type
    Affected if The platform is ASR 5000 Series Router or Virtualized Packet Core running Cisco StarOS
  2. Check the installed StarOS version
    Execute 'show version' or 'show software' command on the StarOS CLI to retrieve the running software version
    Affected if The installed version matches exactly 19.4.2.65120, 19.6.0, 21.2.0, 21.2.6, or 21.4.0
  3. Verify IPsec Manager service is enabled
    Execute 'show ipsecmgr' or 'show service' command to confirm the ipsecmgr service is configured and running
    Affected if The ipsecmgr service is active on the system
  4. Confirm IKEv2/IPsec VPN is configured
    Execute 'show ipsec' or 'show ikev2' configuration and session status commands to check for active IKEv2 security associations or IPsec tunnel configurations
    Affected if IKEv2-based IPsec VPN tunnels are configured or active on the device

A system is affected if it runs Cisco StarOS on ASR 5000 Series or Virtualized Packet Core with version 19.4.2.65120, 19.6.0, 21.2.0, 21.2.6, or 21.4.0 and has the IPsec Manager service enabled with IKEv2 configurations.

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

Apply the Cisco patch for bug CSCve29605 by upgrading to a fixed StarOS version. Schedule a maintenance window to minimize disruption, as the IPsec service will be impacted during the upgrade.

Fix this in Staros Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA1.0 h
10.0 hours of engineering $1,750
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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-2018-0273 in production — separate from our analysis above.

No notes yet

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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