CVE-2017-18344: High severity Linux Linux kernel vulnerability

Published Dec 15, 2017
·
Updated

A flaw was found in kernel versions before 4.14.8. The timercreate syscall implementation in kernel/time/posix-timers.c in the Linux kernel before 4.14.8 doesn't properly validate the sigevent->sigevnotify field, which leads to out-of-bounds access in the showtimer function (called when /proc/$PID/timers is read). This allows userspace applications to read arbitrary kernel memory (on a kernel built with CONFIGPOSIXTIMERS and CONFIGCHECKPOINTRESTORE).

References:

http://seclists.org/oss-sec/2018/q3/76

An upstream patch:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=cef31d9af908243421258f1df35a4a644604efbe

Other sources

The timercreate syscall implementation in kernel/time/posix-timers.c in the Linux kernel doesn't properly validate the sigevent->sigevnotify field, which leads to out-of-bounds access in the showtimer function.

Affected Software

25 affected componentsFixes available
redhat/kernel-rt<0:3.10.0-957.rt56.910.el7
0:3.10.0-957.rt56.910.el7
redhat/kernel-alt<0:4.14.0-115.el7a
0:4.14.0-115.el7a
redhat/kernel<0:3.10.0-957.el7
0:3.10.0-957.el7
redhat/kernel<0:3.10.0-327.76.1.el7
0:3.10.0-327.76.1.el7
redhat/kernel<0:3.10.0-514.61.1.el7
0:3.10.0-514.61.1.el7
redhat/kernel<0:3.10.0-693.43.1.el7
0:3.10.0-693.43.1.el7
redhat/kernel<0:3.10.0-862.20.2.el7
0:3.10.0-862.20.2.el7
redhat/kernel-rt<1:3.10.0-693.43.1.rt56.630.el6
1:3.10.0-693.43.1.rt56.630.el6
redhat/kernel<4.14.8
4.14.8
Linux Linux kernel<4.14.8
Canonical Ubuntu Linux=12.04
Canonical Ubuntu Linux=14.04
redhat Mrg Realtime=2.0
redhat Enterprise Linux Desktop=7.0
redhat Enterprise Linux Server=7.0
redhat Enterprise Linux Server Aus=7.2
redhat Enterprise Linux Server Aus=7.3
redhat Enterprise Linux Server Aus=7.4
redhat Enterprise Linux Server Eus=7.3
redhat Enterprise Linux Server Eus=7.5
redhat Enterprise Linux Server Tus=7.2
redhat Enterprise Linux Server Tus=7.3
redhat Enterprise Linux Server Tus=7.4
redhat Enterprise Linux Workstation=7.0
debian/linux
6.1.176-16.1.180-16.12.94-16.12.107-17.1.12-17.1.13-1

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade redhat/kernel-rt to a version that resolves this vulnerability.

    Fixed in 0:3.10.0-957.rt56.910.el7
  2. Upgrade

    Upgrade redhat/kernel-alt to a version that resolves this vulnerability.

    Fixed in 0:4.14.0-115.el7a
  3. Upgrade

    Upgrade redhat/kernel to a version that resolves this vulnerability.

    Fixed in 0:3.10.0-957.el7
  4. Upgrade

    Upgrade redhat/kernel to a version that resolves this vulnerability.

    Fixed in 0:3.10.0-327.76.1.el7
  5. Upgrade

    Upgrade redhat/kernel to a version that resolves this vulnerability.

    Fixed in 0:3.10.0-514.61.1.el7
  6. Upgrade

    Upgrade redhat/kernel to a version that resolves this vulnerability.

    Fixed in 0:3.10.0-693.43.1.el7
  7. Upgrade

    Upgrade redhat/kernel to a version that resolves this vulnerability.

    Fixed in 0:3.10.0-862.20.2.el7
  8. Upgrade

    Upgrade redhat/kernel-rt to a version that resolves this vulnerability.

    Fixed in 1:3.10.0-693.43.1.rt56.630.el6
  9. Upgrade

    Upgrade redhat/kernel to a version that resolves this vulnerability.

    Fixed in 4.14.8
  10. Upgrade

    Upgrade debian/linux to a version that resolves this vulnerability.

    Fixed in 6.1.176-1Fixed in 6.1.180-1Fixed in 6.12.94-1Fixed in 6.12.107-1Fixed in 7.1.12-1Fixed in 7.1.13-1

Event History

Dec 15, 2017
CVE Published
12:00 AM
Jul 26, 2018
CVE Published
via MITRE·07:00 PM
Data Sourced
via MITRE·07:00 PM
Description
Data Sourced
via NVD·07:29 PM
RemedyDescriptionSeverityWeaknessAffected Software
Jan 11, 2024
Data Sourced
via Launchpad·10:37 PM
Description
Jul 4, 2026
Data Sourced
via Ubuntu·11:04 AM
RemedyDescriptionSeverityAffected Software
Sep 4, 2026
Data Sourced
via Debian·12:24 PM
DescriptionAffected Software

Parent advisories

This vulnerability appears in the following advisories.

Frequently Asked Questions

1

What is CVE-2017-18344?

CVE-2017-18344 is a vulnerability that affects the timer_create syscall implementation in the Linux kernel.

2

What is the severity of CVE-2017-18344?

CVE-2017-18344 has a severity level of high (7).

3

How does CVE-2017-18344 affect Linux?

CVE-2017-18344 leads to an out-of-bounds access in the show_timer function of the Linux kernel.

4

Which versions of Linux are affected by CVE-2017-18344?

Linux kernel versions before 4.14.8 are affected by CVE-2017-18344.

5

How can I fix CVE-2017-18344?

To fix CVE-2017-18344, update your Linux kernel to version 4.14.8 or later.

Company

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