MSRC_CVE-2021-26443

Vulnerability from csaf_microsoft - Published: 2021-11-09 08:00 - Updated: 2021-11-12 08:00
Summary
Microsoft Virtual Machine Bus (VMBus) Remote Code Execution Vulnerability

Notes

Additional Resources
To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle
Disclaimer
The information provided in the Microsoft Knowledge Base is provided \"as is\" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.
Customer Action
Required. The vulnerability documented by this CVE requires customer action to resolve.

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        "text": "The information provided in the Microsoft Knowledge Base is provided \\\"as is\\\" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.",
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          "title": "Assigning CNA"
        },
        {
          "category": "faq",
          "text": "A remote code execution vulnerability exists when a VM guest fails to properly handle communication on a VMBus channel. To exploit the vulnerability, an authenticated attacker could send a specially crafted communication on the VMBus channel from the guest VM to the Host. An attacker who successfully exploited the vulnerability could execute arbitrary code on the host operating system.\nIf the guest VM is running nested VMs, then this machine becomes a host and is vulnerable to CVE-2021-26443 and the update will need to be applied to mitigate this vulnerability.  If the Guest VM is not running nested VMs then the Guest VM is not vulnerable to CVE-2021-26443.\n** Is my system at risk to CVE-2021-26443 if Hyper-V is not enabled?**\nNo.",
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          "url": "https://msrc.microsoft.com/csaf/advisories/2021/msrc_cve-2021-26443.json"
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      "scores": [
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            "attackVector": "ADJACENT_NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 9.0,
            "baseSeverity": "CRITICAL",
            "confidentialityImpact": "HIGH",
            "environmentalsScore": 0.0,
            "exploitCodeMaturity": "UNPROVEN",
            "integrityImpact": "HIGH",
            "privilegesRequired": "LOW",
            "remediationLevel": "OFFICIAL_FIX",
            "reportConfidence": "CONFIRMED",
            "scope": "CHANGED",
            "temporalScore": 7.8,
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:U/RL:O/RC:C",
            "version": "3.1"
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          ]
        }
      ],
      "threats": [
        {
          "category": "impact",
          "details": "Remote Code Execution"
        },
        {
          "category": "exploit_status",
          "details": "Publicly Disclosed:No;Exploited:No;Latest Software Release:Exploitation Less Likely;Older Software Release:Exploitation Less Likely"
        }
      ],
      "title": "Microsoft Virtual Machine Bus (VMBus) Remote Code Execution Vulnerability"
    }
  ]
}


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Sightings

Author Source Type Date

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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