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FreeBSD: VID-AB437561-47C0-11EE-8E38-002590C1F29C (CVE-2023-3494): FreeBSD -- bhyve privileged guest escape via fwctl

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FreeBSD: VID-AB437561-47C0-11EE-8E38-002590C1F29C (CVE-2023-3494): FreeBSD -- bhyve privileged guest escape via fwctl

Severity
4
CVSS
(AV:L/AC:M/Au:N/C:P/I:P/A:P)
Published
08/01/2023
Created
09/05/2023
Added
08/31/2023
Modified
08/31/2023

Description

The fwctl driver implements a state machine which is executed when a bhyve guest accesses certain x86 I/O ports. The interface lets the guest copy a string into a buffer resident in the bhyve process' memory. A bug in the state machine implementation can result in a buffer overflowing when copying this string. Malicious, privileged software running in a guest VM can exploit the buffer overflow to achieve code execution on the host in the bhyve userspace process, which typically runs as root, mitigated by the capabilities assigned through the Capsicum sandbox available to the bhyve process.

Solution(s)

  • freebsd-upgrade-base-13_1-release-p9
  • freebsd-upgrade-base-13_2-release-p2

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