CVE-2016-3699: High severity linux kernel vulnerability
A vulnerability was found in the RHEL7.2 kernel. When RHEL 7.2 is booted with UEFI Secure Boot enabled, securelevel is set. The kernel uses the state of securelevel to prevent userspace from inserting untrusted privileged code at runtime.
The ACPI tables provided by firmware can be overwritten using the initrd. From the kernel documentation:
If the ACPIINITRDTABLEOVERRIDE compile option is true, it is possible to override nearly any ACPI table provided by the BIOS with an instrumented, modified one.
RHEL 7.2 has CONFIGACPIINITRDTABLEOVERRIDE kernel config option enabled, and will load ACPI tables appended to the initrd, even if booted with UEFI Secure Boot enabled and securelevel set.
Upstream patch:
https://github.com/mjg59/linux/commit/a4a5ed2835e8ea042868b7401dced3f517cafa76
Other sources
The Linux kernel, as used in Red Hat Enterprise Linux 7.2 and Red Hat Enterprise MRG 2 and when booted with UEFI Secure Boot enabled, allows local users to bypass intended Secure Boot restrictions and execute untrusted code by appending ACPI tables to the initrd.
Affected Software
Remediation
Patch Available
Event History
Parent advisories
This vulnerability appears in the following advisories.
Frequently Asked Questions
What is the severity of CVE-2016-3699?
CVE-2016-3699 is rated as a high severity vulnerability due to its potential to allow untrusted code execution.
How do I fix CVE-2016-3699?
To fix CVE-2016-3699, you should update to the latest kernel version provided by Red Hat, such as kernel-rt 0:3.10.0-514.rt56.420.el7 or kernel 0:3.10.0-514.el7.
Which versions of Red Hat are affected by CVE-2016-3699?
CVE-2016-3699 affects RHEL 7.2 and its specific kernel versions.
What does CVE-2016-3699 impact?
CVE-2016-3699 impacts the kernel's handling of UEFI Secure Boot and could allow unauthorized kernel modifications.
Is CVE-2016-3699 specific to certain architectures?
CVE-2016-3699 is not architecture-specific and affects the Linux kernel across supported platforms.