CVE-2020-14311
Published: 29 July 2020
There is an issue with grub2 before version 2.06 while handling symlink on ext filesystems. A filesystem containing a symbolic link with an inode size of UINT32_MAX causes an arithmetic overflow leading to a zero-sized memory allocation with subsequent heap-based buffer overflow.
From the Ubuntu Security Team
Chris Coulson discovered that multiple integer overflows existed in GRUB2 when handling certain filesystems, font files or PNG images, leading to heap-based buffer overflows. A local attacker could use these to execute arbitrary code and bypass UEFI Secure Boot restrictions.
Notes
| Author | Note |
|---|---|
| alexmurray | grub2-signed is not supported in Ubuntu 12.04 ESM (precise/esm) and so marking the priority for grub2 in this release as low |
Priority
Status
| Package | Release | Status |
|---|---|---|
|
grub2 Launchpad, Ubuntu, Debian |
jammy |
Not vulnerable
(2.06-2ubuntu7)
|
| kinetic |
Not vulnerable
(2.06-2ubuntu12)
|
|
| lunar |
Not vulnerable
(2.06-2ubuntu16)
|
|
| groovy |
Not vulnerable
(2.04-1ubuntu26.1)
|
|
| bionic |
Released
(2.02-2ubuntu8.16)
|
|
| focal |
Released
(2.04-1ubuntu26.1)
|
|
| hirsute |
Not vulnerable
(2.04-1ubuntu26.1)
|
|
| trusty |
Released
(2.02~beta2-9ubuntu1.20)
Available with Ubuntu Pro or Ubuntu Pro (Infra-only) |
|
| upstream |
Needs triage
|
|
| xenial |
Released
(2.02~beta2-36ubuntu3.26)
|
|
|
grub2-signed Launchpad, Ubuntu, Debian |
jammy |
Not vulnerable
(1.182~22.04.1)
|
| kinetic |
Not vulnerable
(1.185)
|
|
| lunar |
Not vulnerable
(1.192)
|
|
| groovy |
Not vulnerable
(1.147)
|
|
| bionic |
Released
(1.93.18)
|
|
| eoan |
Ignored
(end of life)
|
|
| focal |
Released
(1.142.3)
|
|
| hirsute |
Not vulnerable
(1.147)
|
|
| trusty |
Released
(1.34.22)
Available with Ubuntu Pro or Ubuntu Pro (Infra-only) |
|
| upstream |
Needs triage
|
|
| xenial |
Released
(1.66.26)
|
|
|
grub2-unsigned Launchpad, Ubuntu, Debian |
trusty |
Does not exist
|
| xenial |
Needed
|
|
| bionic |
Released
(2.04-1ubuntu47.4)
|
|
| focal |
Released
(2.04-1ubuntu47.4)
|
|
| jammy |
Not vulnerable
(2.06-2ubuntu7)
|
|
| kinetic |
Not vulnerable
(2.06-2ubuntu12)
|
|
| lunar |
Not vulnerable
(2.06-2ubuntu16)
|
|
| upstream |
Needs triage
|
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score | 5.7 |
| Attack vector | Local |
| Attack complexity | High |
| Privileges required | High |
| User interaction | None |
| Scope | Unchanged |
| Confidentiality | None |
| Integrity impact | High |
| Availability impact | High |
| Vector | CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:H/A:H |
References
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-14311
- https://www.eclypsium.com/2020/07/29/theres-a-hole-in-the-boot/
- https://wiki.ubuntu.com/SecurityTeam/KnowledgeBase/GRUB2SecureBootBypass
- https://www.openwall.com/lists/oss-security/2020/07/29/3
- https://lists.gnu.org/archive/html/grub-devel/2020-07/msg00034.html
- https://ubuntu.com/security/notices/USN-4432-1
- NVD
- Launchpad
- Debian