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Amazon Linux AMI : kernel (ALAS-2017-845) (Stack Clash)

high Nessus Plugin ID 100874

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Synopsis

The remote Amazon Linux AMI host is missing a security update.

Description

An issue was discovered in the size of the stack guard page on Linux, specifically a 4k stack guard page is not sufficiently large and can be jmp'ed over, this affects Linux Kernel versions 4.11.5 and earlier (the stackguard page was introduced in 2010). (CVE-2017-1000364)

The offset2lib patch as used by the Linux Kernel contains a vulnerability, if RLIMIT_STACK is set to RLIMIT_INFINITY and 1 Gigabyte of memory is allocated (the maximum under the 1/4 restriction) then the stack will be grown down to 0x80000000, and as the PIE binary is mapped above 0x80000000 the minimum distance between the end of the PIE binary's read-write segment and the start of the stack becomes small enough that the stack guard page can be jumped over by an attacker. This is a different issue than CVE-2017-1000370 and CVE-2017-1000365 . (CVE-2017-1000371)

Solution

Run 'yum update kernel' to update your system.

See Also

https://alas.aws.amazon.com/ALAS-2017-845.html

Plugin Details

Severity: High

ID: 100874

File Name: ala_ALAS-2017-845.nasl

Version: 3.9

Type: local

Agent: unix

Published: 6/20/2017

Updated: 4/10/2019

Supported Sensors: Frictionless Assessment AWS, Frictionless Assessment Agent, Nessus Agent, Agentless Assessment, Nessus

Risk Information

VPR

Risk Factor: High

Score: 7.4

CVSS v2

Risk Factor: High

Base Score: 7.2

Temporal Score: 6

Vector: CVSS2#AV:L/AC:L/Au:N/C:C/I:C/A:C

CVSS v3

Risk Factor: High

Base Score: 7.8

Temporal Score: 7.2

Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Temporal Vector: CVSS:3.0/E:F/RL:O/RC:C

Vulnerability Information

CPE: p-cpe:/a:amazon:linux:kernel, p-cpe:/a:amazon:linux:kernel-debuginfo, p-cpe:/a:amazon:linux:kernel-debuginfo-common-i686, p-cpe:/a:amazon:linux:kernel-debuginfo-common-x86_64, p-cpe:/a:amazon:linux:kernel-devel, p-cpe:/a:amazon:linux:kernel-doc, p-cpe:/a:amazon:linux:kernel-headers, p-cpe:/a:amazon:linux:kernel-tools, p-cpe:/a:amazon:linux:kernel-tools-debuginfo, p-cpe:/a:amazon:linux:kernel-tools-devel, p-cpe:/a:amazon:linux:perf, p-cpe:/a:amazon:linux:perf-debuginfo, cpe:/o:amazon:linux

Required KB Items: Host/local_checks_enabled, Host/AmazonLinux/release, Host/AmazonLinux/rpm-list

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 6/19/2017

Exploitable With

Metasploit (rsh_stack_clash_priv_esc.rb)

Reference Information

CVE: CVE-2017-1000364, CVE-2017-1000371

ALAS: 2017-845