05 December 2018
Protect yourself against future threats.
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2018.3762 Insufficient bounds checking in bhyve(8) device model 5 December 2018 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: bhyve Publisher: FreeBSD Operating System: FreeBSD Impact/Access: Execute Arbitrary Code/Commands -- Existing Account Resolution: Patch/Upgrade CVE Names: CVE-2018-17160 Original Bulletin: https://security.freebsd.org/advisories/FreeBSD-SA-18:14.bhyve.asc - --------------------------BEGIN INCLUDED TEXT-------------------- - -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 ============================================================================= FreeBSD-SA-18:14.bhyve Security Advisory The FreeBSD Project Topic: Insufficient bounds checking in bhyve(8) device model Category: core Module: bhyve Announced: 2018-12-04 Credits: Reno Robert Affects: All supported versions of FreeBSD. Corrected: 2018-12-04 18:32:50 UTC (stable/11, 11.2-STABLE) 2018-12-04 18:38:32 UTC (releng/11.2, 11.2-RELEASE-p6) CVE Name: CVE-2018-17160 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 The bhyve hypervisor uses the bhyve(8) program to emulate support for most virtual devices used by guest operating systems. II. Problem Description Insufficient bounds checking in one of the device models provided by bhyve(8) can permit a guest operating system to overwrite memory in the bhyve(8) processing possibly permitting arbitary code execution. III. Impact A guest OS using a firmware image can cause the bhyve process to crash, or possibly execute arbitrary code on the host as root. IV. Workaround The device model in question is only enabled when booting guests with a firmware image such as the UEFI images from the bhyve-firmware package. Guests booted using bhyveload(8) or grub2-bhyve are not affected. Guests using operating systems supported by bhyveload(8) or grub2-bhyve can be booted using these tools as a workaround. No workaround is available for guest operating systems such as Windows that require a firmware image. V. Solution Perform one of the following: Upgrade your vulnerable system to a supported FreeBSD stable or release / security branch (releng) dated after the correction date. 1) To update your vulnerable system via a binary patch: Systems running a RELEASE version of FreeBSD on the i386 or amd64 platforms can be updated via the freebsd-update(8) utility: # freebsd-update fetch # freebsd-update install Afterward, restart guests using firmware images. 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-18:14/bhyve.patch # fetch https://security.FreeBSD.org/patches/SA-18:14/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>. Afterward, restart guests using firmware images. VI. Correction details The following list contains the correction revision numbers for each affected branch. Branch/path Revision - - ------------------------------------------------------------------------- stable/11/ r341486 releng/11.2/ r341488 - - ------------------------------------------------------------------------- To see which files were modified by a particular revision, run the following command, replacing NNNNNN with the revision number, on a machine with Subversion installed: # svn diff -cNNNNNN --summarize svn://svn.freebsd.org/base Or visit the following URL, replacing NNNNNN with the revision number: <URL:https://svnweb.freebsd.org/base?view=revision&revision=NNNNNN> VII. References <URL:https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-17160> The latest revision of this advisory is available at <URL:https://security.FreeBSD.org/advisories/FreeBSD-SA-18:14.bhyve.asc> - -----BEGIN PGP SIGNATURE----- iQKTBAEBCgB9FiEE/A6HiuWv54gCjWNV05eS9J6n5cIFAlwGykdfFIAAAAAALgAo aXNzdWVyLWZwckBub3RhdGlvbnMub3BlbnBncC5maWZ0aGhvcnNlbWFuLm5ldEZD MEU4NzhBRTVBRkU3ODgwMjhENjM1NUQzOTc5MkY0OUVBN0U1QzIACgkQ05eS9J6n 5cKcIQ/+Ktt7+SZPoWZQmJv6LdT6qI+na0+/9LDwBoC+Tj37heFUnhcMTxDDH4o3 nexELxF1xHmRchooRKfJr7npa8CF4jBzp2PSb+783q6TrFKe90ohlmt56lRB6gJg 3IJX5TxvAvLsqTgwPyALqyy3H5C8cY3btHPsZIArK0WVRTB74K3mr3L3IRVTcMCv 9cbUZyDO21ZIDTB5h9FYGo+6bg8hvZztmromkxssqlKKS8TUltGr/H3k6EHlnEA9 rG+6kswIgyeXNFrdksD6ni7L5Z3lwR/DFiU2d/lageQZ6vgDUa3c0KMhepfelfJR AiUtGpgfCDuHZ1NV2uyr9I6nPRHhdxPy3o2bF/B7+SLdn03tcZiO0tx3Wf68EQlt jAYFuup7+TFKoupsHlb2fkQxNOeQCr6dF+ikJDVgwCqmx2zn9tDo/tWoNdH+Jylx MDKsE369HOSRGR3Ua1ELEtOEzbGbcUHJyT6I1E2poctE61hYI+5te6pasY3ReN68 vyFMAo5ey0kJ6mi2YVcvDo2ZEb/GP1noJkdquYpIm8Ko0TPtivaMHXLIPcpLiJUc fBZexGCXJnb8f6ClMMU12U6f3H35Hz1AUPG3MSWHGgoczQBZJ8PECJ+r0X5bhkzW Ymlksu/HprW4tFLCdD4mB7lewvr3qpmoRoS1KwgMoXnRKzPbGsc= =4zGb - -----END PGP SIGNATURE----- - --------------------------END INCLUDED TEXT-------------------- You have received this e-mail bulletin as a result of your organisation's registration with AusCERT. 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It may not be updated when updates to the original are made. If downloading at a later date, it is recommended that the bulletin is retrieved directly from the author's website to ensure that the information is still current. Contact information for the authors of the original document is included in the Security Bulletin above. If you have any questions or need further information, please contact them directly. Previous advisories and external security bulletins can be retrieved from: https://www.auscert.org.au/bulletins/ =========================================================================== Australian Computer Emergency Response Team The University of Queensland Brisbane Qld 4072 Internet Email: firstname.lastname@example.org Facsimile: (07) 3365 7031 Telephone: (07) 3365 4417 (International: +61 7 3365 4417) AusCERT personnel answer during Queensland business hours which are GMT+10:00 (AEST). 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