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  • FreeBSD Security Advisory FreeBSD-SA-24:15.bhyve

    From FreeBSD Security Advisories@21:1/5 to All on Thu Sep 19 16:00:07 2024
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    ============================================================================= FreeBSD-SA-24:15.bhyve Security Advisory
    The FreeBSD Project

    Topic: bhyve(8) out-of-bounds read access via XHCI emulation

    Category: core
    Module: bhyve
    Announced: 2024-09-19
    Credits: Synacktiv
    Sponsored by: The FreeBSD Foundation, The Alpha-Omega Project
    Affects: All supported versions of FreeBSD.
    Corrected: 2024-09-19 12:40:17 UTC (stable/14, 14.1-STABLE)
    2024-09-19 13:30:18 UTC (releng/14.1, 14.1-RELEASE-p5)
    2024-09-19 13:30:44 UTC (releng/14.0, 14.0-RELEASE-p11)
    2024-09-19 12:48:52 UTC (stable/13, 13.4-STABLE)
    2024-09-19 13:35:06 UTC (releng/13.4, 13.4-RELEASE-p1)
    2024-09-19 13:35:37 UTC (releng/13.3, 13.3-RELEASE-p7)
    CVE Name: CVE-2024-41721

    For general information regarding FreeBSD Security Advisories,
    including descriptions of the fields above, security branches, and the following sections, please visit <URL:https://security.FreeBSD.org/>.

    I. Background

    bhyve(8) is a hypervisor that runs guest operating systems inside a virtual machine.

    II. Problem Description

    bhyve can be configured to emulate devices on a virtual USB controller (XHCI), such as USB tablet devices. An insufficient boundary validation in the USB code could lead to an out-of-bounds read on the heap, which could potentially lead to an arbitrary write and remote code execution.

    III. Impact

    A malicious, privileged software running in a guest VM can exploit the vulnerability to crash the hypervisor process or potentially achieve code execution on the host in the bhyve userspace process, which typically runs as root. Note that bhyve runs in a Capsicum sandbox, so malicious code is constrained by the capabilities available to the bhyve process.

    IV. Workaround

    No workaround is available, but guests that do not use XHCI emulation are not impacted.

    V. Solution

    Upgrade your vulnerable system to a supported FreeBSD stable or
    release / security branch (releng) dated after the correction date.

    Guest operating systems emulating USB devices with XHCI need to be restarted for
    the correction to be applied (i.e., their corresponding bhyve process needs to be terminated and started again).

    Perform one of the following:

    1) To update your vulnerable system via a binary patch:

    Systems running a RELEASE version of FreeBSD on the amd64 or arm64 platforms, or the i386 platform on FreeBSD 13, can be updated via the freebsd-update(8) utility:

    # freebsd-update fetch
    # freebsd-update install

    2) To update your vulnerable system via a source code patch:

    The following patches have been verified to apply to the applicable
    FreeBSD release branches.

    a) Download the relevant patch from the location below, and verify the
    detached PGP signature using your PGP utility.

    # fetch https://security.FreeBSD.org/patches/SA-24:15/bhyve.patch
    # fetch https://security.FreeBSD.org/patches/SA-24:15/bhyve.patch.asc
    # gpg --verify bhyve.patch.asc

    b) Apply the patch. Execute the following commands as root:

    # cd /usr/src
    # patch < /path/to/patch

    c) Recompile the operating system using buildworld and installworld as described in <URL:https://www.FreeBSD.org/handbook/makeworld.html>.

    Restart the corresponding bhyve processes, or reboot the system.

    VI. Correction details

    This issue is corrected as of the corresponding Git commit hash in the following stable and release branches:

    Branch/path Hash Revision
    - ------------------------------------------------------------------------- stable/14/ 419da61f8203 stable/14-n268745 releng/14.1/ 3c6c0dcb5acb releng/14.1-n267716 releng/14.0/ ba46f1174972 releng/14.0-n265453 stable/13/ 2abd2ad64899 stable/13-n258347 releng/13.4/ 5f035df278cc releng/13.4-n258258 releng/13.3/ e7a790dc3ffe releng/13.3-n257468
    - -------------------------------------------------------------------------

    Run the following command to see which files were modified by a
    particular commit:

    # git show --stat <commit hash>

    Or visit the following URL, replacing NNNNNN with the hash:

    <URL:https://cgit.freebsd.org/src/commit/?id=NNNNNN>

    To determine the commit count in a working tree (for comparison against
    nNNNNNN in the table above), run:

    # git rev-list --count --first-parent HEAD

    VII. References

    The corresponding part of the security audit report as provided by Synacktiv will be published in due course.

    <URL:https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2024-41721>

    The latest revision of this advisory is available at <URL:https://security.FreeBSD.org/advisories/FreeBSD-SA-24:15.bhyve.asc> -----BEGIN PGP SIGNATURE-----

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