CVE-2020-10713

Published: 29 July 2020

A flaw was found in grub2, prior to version 2.06. An attacker may use the GRUB 2 flaw to hijack and tamper the GRUB verification process. This flaw also allows the bypass of Secure Boot protections. In order to load an untrusted or modified kernel, an attacker would first need to establish access to the system such as gaining physical access, obtain the ability to alter a pxe-boot network, or have remote access to a networked system with root access. With this access, an attacker could then craft a string to cause a buffer overflow by injecting a malicious payload that leads to arbitrary code execution within GRUB. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

From the Ubuntu Security Team

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.

Notes

grub2-signed is not supported in Ubuntu 12.04 ESM (precise/esm) and so marking the priority for grub2 in this release as low

Status

Severity score breakdown

References

• https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-10713
• https://www.eclypsium.com/2020/07/29/theres-a-hole-in-the-boot/
• https://wiki.ubuntu.com/SecurityTeam/KnowledgeBase/GRUB2SecureBootBypass
• https://lists.gnu.org/archive/html/grub-devel/2020-07/msg00034.html
• https://www.openwall.com/lists/oss-security/2020/07/29/3
• https://ubuntu.com/security/notices/USN-4432-1
• NVD
• Launchpad
• Debian