Synopsis

Important: kernel security update

Type/Severity

Security Advisory: Important

Topic

An update for kernel is now available for Red Hat Enterprise Linux 5 Extended
Lifecycle Support.

Red Hat Product Security has rated this update as having a security impact of
Important. A Common Vulnerability Scoring System (CVSS) base score, which gives
a detailed severity rating, is available for each vulnerability from the CVE
link(s) in the References section.

Description

The kernel packages contain the Linux kernel, the core of any Linux operating
system.

Security Fix(es):

• A flaw was found in the way memory was being allocated on the stack for user

space binaries. If heap (or different memory region) and stack memory regions
were adjacent to each other, an attacker could use this flaw to jump over the
stack guard gap, cause controlled memory corruption on process stack or the
adjacent memory region, and thus increase their privileges on the system. This
is a kernel-side mitigation which increases the stack guard gap size from one
page to 1 MiB to make successful exploitation of this issue more difficult.
(CVE-2017-1000364, Important)

Red Hat would like to thank Qualys Research Labs for reporting this issue.

Solution

For details on how to apply this update, which includes the changes described in
this advisory, refer to:

https://access.redhat.com/articles/11258

The system must be rebooted for this update to take effect.

Affected Products

• Red Hat Enterprise Linux Server - Extended Life Cycle Support 5 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 5 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support (for IBM z Systems) 5 s390x

Fixes

• BZ - 1461333 - CVE-2017-1000364 kernel: heap/stack gap jumping via unbounded stack allocations

CVEs

• CVE-2017-1000364
• CVE-2017-1000379

References