This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --===============1752427743668957868== Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="ANa4kO8L0rvPBki9dpbBNhpfuWlwUABEF"
This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --ANa4kO8L0rvPBki9dpbBNhpfuWlwUABEF Content-Type: multipart/mixed; boundary="sYv0AKUnQAskTT49xg4wzJcIUUPzWN7wa"
--sYv0AKUnQAskTT49xg4wzJcIUUPzWN7wa Content-Type: text/plain; charset=utf-8 Content-Language: en-U Content-Transfer-Encoding: quoted-printable
========================================================================== Ubuntu Security Notice USN-4432-1 July 29, 2020
grub2, grub2-signed vulnerabilities ==========================================================================
A security issue affects these releases of Ubuntu and its derivatives:
- Ubuntu 20.04 LTS - Ubuntu 18.04 LTS - Ubuntu 16.04 LTS - Ubuntu 14.04 ESM
Summary:
Several security issues were fixed in GRUB 2.
Software Description: - grub2: GRand Unified Bootloader - grub2-signed: GRand Unified Bootloader
Details:
Jesse Michael and Mickey Shkatov discovered that the configuration parser in GRUB2 did not properly exit when errors were discovered, resulting in heap-based buffer overflows. A local attacker could use this to execute arbitrary code and bypass UEFI Secure Boot restrictions. (CVE-2020-10713)
Chris Coulson discovered that the GRUB2 function handling code did not properly handle a function being redefined, leading to a use-after-free vulnerability. A local attacker could use this to execute arbitrary code and bypass UEFI Secure Boot restrictions. (CVE-2020-15706)
Chris Coulson discovered that multiple integer overflows existed in GRUB2 when handling certain filesystems or font files, leading to heap-based buffer overflows. A local attacker could use these to execute arbitrary code and bypass UEFI Secure Boot restrictions. (CVE-2020-14309, CVE-2020-14310, CVE-2020-14311)
It was discovered that the memory allocator for GRUB2 did not validate allocation size, resulting in multiple integer overflows and heap-based buffer overflows when handling certain filesystems, PNG images or disk metadata. A local attacker could use this to execute arbitrary code and bypass UEFI Secure Boot restrictions. (CVE-2020-14308)
Mathieu Trudel-Lapierre discovered that in certain situations, GRUB2 failed to validate kernel signatures. A local attacker could use this to bypass Secure Boot restrictions. (CVE-2020-15705)
Colin Watson and Chris Coulson discovered that an integer overflow existed in GRUB2 when handling the initrd command, leading to a heap-based buffer overflow. A local attacker could use this to execute arbitrary code and bypass UEFI Secure Boot restrictions. (CVE-2020-15707)
Update instructions:
The problem can be corrected by updating your system to the following package versions:
Ubuntu 20.04 LTS: grub-efi-amd64-bin 2.04-1ubuntu26.1 grub-efi-amd64-signed 1.142.3+2.04-1ubuntu26.1 grub-efi-arm-bin 2.04-1ubuntu26.1 grub-efi-arm64-bin 2.04-1ubuntu26.1 grub-efi-arm64-signed 1.142.3+2.04-1ubuntu26.1 grub-efi-ia32-bin 2.04-1ubuntu26.1
Ubuntu 18.04 LTS: grub-efi-amd64-bin 2.02-2ubuntu8.16 grub-efi-amd64-signed 1.93.18+2.02-2ubuntu8.16 grub-efi-arm-bin 2.02-2ubuntu8.16 grub-efi-arm64-bin 2.02-2ubuntu8.16 grub-efi-arm64-signed 1.93.18+2.02-2ubuntu8.16 grub-efi-ia32-bin 2.02-2ubuntu8.16 grub-efi-ia64-bin 2.02-2ubuntu8.16
Ubuntu 16.04 LTS: grub-efi-amd64-bin 2.02~beta2-36ubuntu3.26 grub-efi-amd64-signed 1.66.26+2.02~beta2-36ubuntu3.26 grub-efi-arm-bin 2.02~beta2-36ubuntu3.26 grub-efi-arm64-bin 2.02~beta2-36ubuntu3.26 grub-efi-arm64-signed 1.66.26+2.02~beta2-36ubuntu3.26 grub-efi-ia32-bin 2.02~beta2-36ubuntu3.26 grub-efi-ia64-bin 2.02~beta2-36ubuntu3.26
Ubuntu 14.04 ESM: grub-efi-amd64-bin 2.02~beta2-9ubuntu1.20 grub-efi-amd64-signed 1.34.22+2.02~beta2-9ubuntu1.20 grub-efi-arm-bin 2.02~beta2-9ubuntu1.20 grub-efi-arm64-bin 2.02~beta2-9ubuntu1.20 grub-efi-ia32-bin 2.02~beta2-9ubuntu1.20 grub-efi-ia64-bin 2.02~beta2-9ubuntu1.20
Fully mitigating these vulnerabilities requires both an updated GRUB2 boot loader and the application of a UEFI Revocation List (dbx) to system firmware. Ubuntu will provide a packaged dbx update at a later time, though system adminstrators may choose to apply a third party dbx update before then. For more details on mitigation steps and the risks entailed (especially for dual/multi-boot scenarios), please see the Knowledge Base article at https://wiki.ubuntu.com/SecurityTeam/KnowledgeBase/GRUB2SecureBootBypass
References: https://usn.ubuntu.com/4432-1 CVE-2020-10713, CVE-2020-14308, CVE-2020-14309, CVE-2020-14310, CVE-2020-14311, CVE-2020-15705, CVE-2020-15706, CVE-2020-15707, https://wiki.ubuntu.com/SecurityTeam/KnowledgeBase/GRUB2SecureBootBypass
Package Information: https://launchpad.net/ubuntu/+source/grub2/2.04-1ubuntu26.1 https://launchpad.net/ubuntu/+source/grub2-signed/1.142.3 https://launchpad.net/ubuntu/+source/grub2/2.02-2ubuntu8.16 https://launchpad.net/ubuntu/+source/grub2-signed/1.93.18 https://launchpad.net/ubuntu/+source/grub2/2.02~beta2-36ubuntu3.26 https://launchpad.net/ubuntu/+source/grub2-signed/1.66.26
--sYv0AKUnQAskTT49xg4wzJcIUUPzWN7wa--
--ANa4kO8L0rvPBki9dpbBNhpfuWlwUABEF Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc"
-----BEGIN PGP SIGNATURE-----
iQEzBAEBCgAdFiEERN//5MGgCOgyKeIFYR+97NWUbg8FAl8hztoACgkQYR+97NWU bg9Q5ggApXrXFFVVpwwcSENEpac2uc5mAls8qA9M/nY4wQzIeGdF3vt+ujLXRk7k cNJNgAp8lCia7t4cStj8B9Uqfd7tXNaRzd+EoJ+Uukezr2Cv2t9GIKzpdjm/kFeE BSWSBUSTrxRex9O75MwHqRmSzLs9ClXL3cPIfHLBJHmYB6aRcwpxJAfPRThASeDN HKvVypDzkGtxkHMOpSSr4/n071sdP7zR0QTpIRNBZNxC7IgfMoukSaAgOclXAUIX 9USPTXJiRxdEnA+nYDjk0NwP13pb1PsmkP0EkrToC7ldkyDmsOPEWVPX0B5hh2fy Kb6r3XEqUB9kuz3OokUnZaDYBxA+aw== =OcTs -----END PGP SIGNATURE-----
--ANa4kO8L0rvPBki9dpbBNhpfuWlwUABEF--
--===============1752427743668957868== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: base64 Content-Disposition: inline
LS0gCnVidW50dS1zZWN1cml0eS1hbm5vdW5jZSBtYWlsaW5nIGxpc3QKdWJ1bnR1LXNlY3VyaXR5 LWFubm91bmNlQGxpc3RzLnVidW50dS5jb20KTW9kaWZ5IHNldHRpbmdzIG9yIHVuc3Vic2NyaWJl IGF0OiBodHRwczovL2xpc3RzLnVidW50dS5jb20vbWFpbG1hbi9saXN0aW5mby91YnVudHUtc2Vj dXJpdHktYW5ub3VuY2UK
--===============1752427743668957868==--
|