Guest escape via untrapped AMD virtualization instructions
Published Mar 26, 2021 · Updated Aug 4, 2024
Guest escape in bhyve on vulnerable FreeBSD releases allows guest OS users with kernel access to take full control of an AMD host. The SVM implementation fails to trap AMD virtualization instructions that accept host physical addresses, so guest operands bypass nested page table translation and can write constrained arbitrary host memory. Exploitation requires kernel-mode execution inside a bhyve guest on an AMD CPU; successful use grants full control of the host.
Summary
What happened
Guest escape in bhyve on vulnerable FreeBSD releases allows guest OS users with kernel access to take full control of an AMD host. The SVM implementation fails to trap AMD virtualization instructions that accept host physical addresses, so guest operands bypass nested page table translation and can write constrained arbitrary host memory. Exploitation requires kernel-mode execution inside a bhyve guest on an AMD CPU; successful use grants full control of the host.
The record
- CVE
- CVE-2020-7467
- Published
- Mar 26, 2021
- Updated
- Aug 4, 2024
- Vendor
- The FreeBSD Project
- Product
- FreeBSD
- Classifications
- CWE-269, T1068
- Attack vector
- physical
- Privileges
- unauthenticated
Timeline
How it unfolded
- Mar 26, 2021CVE publishedPublication date reported by the CVE source.
- Aug 4, 2024Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=FreeBSD 12.1-RELEASE before p10, 11.4-RELEASE before p4, 11.3-RELEASE before p14
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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