#VU34141 Incorrect default permissions in Linux kernel - CVE-2019-20908
Published: July 16, 2020 / Updated: August 8, 2020
Vulnerability identifier: #VU34141
Vulnerability risk: Low
CVSSv4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2019-20908
CWE-ID: CWE-276
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerable software:
Linux kernel
Linux kernel
Software vendor:
Linux Foundation
Linux Foundation
Description
The vulnerability allows a local privileged user to execute arbitrary code.
An issue was discovered in drivers/firmware/efi/efi.c in the Linux kernel before 5.4. Incorrect access permissions for the efivar_ssdt ACPI variable could be used by attackers to bypass lockdown or secure boot restrictions, aka CID-1957a85b0032.
Remediation
Install update from vendor's website.
External links
- http://lists.opensuse.org/opensuse-security-announce/2020-08/msg00009.html
- http://www.openwall.com/lists/oss-security/2020/07/20/6
- http://www.openwall.com/lists/oss-security/2020/07/29/3
- http://www.openwall.com/lists/oss-security/2020/07/30/2
- http://www.openwall.com/lists/oss-security/2020/07/30/3
- https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.4
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=1957a85b0032a81e6482ca4aab883643b8dae06e
- https://git.zx2c4.com/american-unsigned-language/tree/american-unsigned-language.sh
- https://mailarchives.bentasker.co.uk/Mirrors/OSSSec/2020/06-Jun/msg00035.html
- https://usn.ubuntu.com/4426-1/
- https://usn.ubuntu.com/4427-1/
- https://usn.ubuntu.com/4439-1/
- https://usn.ubuntu.com/4440-1/