#VU32926 Race condition in grub - CVE-2020-15706
Published: July 30, 2020
Vulnerability identifier: #VU32926
Vulnerability risk: Low
CVSSv4.0: CVSS:4.0/AV:P/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2020-15706
CWE-ID: CWE-362
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerable software:
grub
grub
Software vendor:
GNU
GNU
Description
The vulnerability allows a local attacker to execute arbitrary code and bypass secure boot restriction.
The vulnerability exists due to a race condition in the "grub_script_function_create()" function. An attacker with physical access can exploit the race and execute arbitrary code on the target system.
Remediation
Install updates from vendor's website.
External links
- http://ubuntu.com/security/notices/USN-4432-1
- http://www.openwall.com/lists/oss-security/2020/07/29/3
- https://access.redhat.com/security/vulnerabilities/grub2bootloader
- https://lists.gnu.org/archive/html/grub-devel/2020-07/msg00034.html
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/ADV200011
- https://wiki.ubuntu.com/SecurityTeam/KnowledgeBase/GRUB2SecureBootBypass
- https://www.debian.org/security/2020/dsa-4735
- https://www.debian.org/security/2020-GRUB-UEFI-SecureBoot
- https://www.eclypsium.com/2020/07/29/theres-a-hole-in-the-boot/
- https://www.openwall.com/lists/oss-security/2020/07/29/3
- https://www.suse.com/c/suse-addresses-grub2-secure-boot-issue/
- https://www.suse.com/support/kb/doc/?id=000019673