A vulnerability seems to have been discovered in the Linux HDLC driver.

This is Yamada from the Systems Department.

The culprit was a very old vulnerability in the Linux kernel announced on March 7th.
Primary source
CVE-2017-2636

kernel through 4.10.1 allows local users to gain privileges or cause a denial of service (double free) by setting the HDLC line discipline. A race condition in the ``.c'' driver can cause local user privilege acquisition and denial of service (double open) via HDLC line control. (slightly appropriate translation)

HDLC (High-Level Data Link Control) is a communication technology that performs point-to-multipoint communication and
was used in modems and ISDN, which are no longer commonplace.

Pihyorohyoro. The screen is Windows

Just because you're not using a modem driver doesn't mean you don't have to worry about
it .

The n_hdlc kernel module will be automatically loaded when an application attempts to use the HDLC line discipline from userspace.

It seems like you need to be careful.

On this page, as a workaround

​# echo "install n_hdlc /bin/true" >> /etc/modprobe.d/disable-n_hdlc.conf

He has posted a countermeasure to prevent the n_hdlc module from being loaded by restarting.

This applies to Red Hat Enterprise Linux 6, 7, and Red Hat Enterprise MRG 2, so
be sure to check the release of these update patches.

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