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Vulnerability of GRUB2: buffer overflow via grub_squash_read_symlink

Synthesis of the vulnerability 

An attacker can trigger a buffer overflow via grub_squash_read_symlink() of GRUB2, in order to trigger a denial of service, and possibly to run code.
Vulnerable software: Debian, Fedora, Windows 10, Windows 2012, Windows 2016, Windows 2019, Windows 8, Windows RT, openSUSE Leap, RHEL, SUSE Linux Enterprise Desktop, SLES, Ubuntu, Unix (platform) ~ not comprehensive.
Severity of this announce: 1/4.
Creation date: 30/07/2020.
Références of this computer vulnerability: ADV200011, CERTFR-2020-AVI-475, CERTFR-2020-AVI-476, CERTFR-2020-AVI-477, CERTFR-2020-AVI-485, CVE-2020-14309, DSA-4735-1, DSA-4735-2, FEDORA-2020-41e57d7649, FEDORA-2020-e19b87f4f5, openSUSE-SU-2020:1168-1, openSUSE-SU-2020:1169-1, RHSA-2020:3216-01, RHSA-2020:3217-01, RHSA-2020:3223-01, RHSA-2020:3227-01, RHSA-2020:3271-01, RHSA-2020:3273-01, RHSA-2020:3274-01, RHSA-2020:3275-01, RHSA-2020:3276-01, SUSE-SU-2020:14440-1, SUSE-SU-2020:2073-1, SUSE-SU-2020:2074-1, SUSE-SU-2020:2076-1, SUSE-SU-2020:2077-1, SUSE-SU-2020:2078-1, SUSE-SU-2020:2079-1, USN-4432-1, USN-4432-2, VIGILANCE-VUL-32953.

Description of the vulnerability 

An attacker can trigger a buffer overflow via grub_squash_read_symlink() of GRUB2, in order to trigger a denial of service, and possibly to run code.
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This weakness announce impacts software or systems such as Debian, Fedora, Windows 10, Windows 2012, Windows 2016, Windows 2019, Windows 8, Windows RT, openSUSE Leap, RHEL, SUSE Linux Enterprise Desktop, SLES, Ubuntu, Unix (platform) ~ not comprehensive.

Our Vigil@nce team determined that the severity of this vulnerability alert is low.

The trust level is of type confirmed by the editor, with an origin of physical access.

An attacker with a expert ability can exploit this computer threat announce.

Solutions for this threat 

GRUB2: patch for BootHole.
A patch is available:
  http://git.savannah.gnu.org/gitweb/?p=grub.git&view=view+git+repository
  https://lists.gnu.org/archive/html/grub-devel/2020-07/msg00034.html
Information sources indicates additional steps.

Debian 10: new grub2 packages.
New packages are available:
  Debian 10: grub2 2.02+dfsg1-20+deb10u2

Fedora 31: new grub2 packages.
New packages are available:
  Fedora 31: grub2 2.02-110.fc31

Fedora 32: new grub2 packages.
New packages are available:
  Fedora 32: grub2 2.04-22.fc32

openSUSE Leap 15: new grub2 packages.
New packages are available:
  openSUSE Leap 15.1: grub2 2.02-lp151.21.21.4
  openSUSE Leap 15.2: grub2 2.04-lp152.7.3.4

RHEL: new grub2 packages.
New packages are available:
  RHEL 7.2: grub2 2.02-0.86.el7_2
  RHEL 7.3: grub2 2.02-0.86.el7
  RHEL 7.4: grub2 2.02-0.86.el7_4
  RHEL 7.6: grub2 2.02-0.86.el7_6
  RHEL 7.7: grub2 2.02-0.86.el7_7
  RHEL 7.8: grub2 2.02-0.86.el7_8
  RHEL 8.0: grub2 2.02-87.el8_0
  RHEL 8.1: grub2 2.02-87.el8_1
  RHEL 8.2: grub2 2.02-87.el8_2

SUSE LE: new grub2 packages.
New packages are available:
  SUSE LE 11 SP4: grub2 2.00-0.66.15.1
  SUSE LE 12 SP2: grub2 2.02~beta2-115.49.1
  SUSE LE 12 SP3: grub2 2.02-4.53.1
  SUSE LE 12 SP4: grub2 2.02-12.31.1
  SUSE LE 12 SP5: grub2 2.02-12.31.1
  SUSE LE 15 RTM: grub2 2.02-19.48.1
  SUSE LE 15 SP1: grub2 2.02-26.25.1
  SUSE LE 15 SP2: grub2 2.04-9.7.1

Ubuntu: new grub packages.
New packages are available:
  Ubuntu 20.04 LTS: grub 2.04-1ubuntu26.2
  Ubuntu 18.04 LTS: grub 2.02-2ubuntu8.17
  Ubuntu 16.04 LTS: grub 2.02~beta2-36ubuntu3.27
  Ubuntu 14.04 ESM: grub 2.02~beta2-9ubuntu1.17-or-21

Windows: solution for BootHole.
The solution is indicated in information sources.
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