Amazon Linux AMI : kernel (ALAS-2017-814)

high Nessus Plugin ID 99418
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Synopsis

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

Description

Possible double free in stcp_sendmsg() (incorrect fix for CVE-2017-5986) :

It was found that the code in net/sctp/socket.c in the Linux kernel through 4.10.1 does not properly restrict association peel-off operations during certain wait states, which allows local users to cause a denial of service (invalid unlock and double free) via a multithreaded application. This vulnerability was introduced by CVE-2017-5986 fix (commit 2dcab5984841).

Reachable BUG_ON from userspace in sctp_wait_for_sndbuf :

It was reported that with Linux kernel, earlier than version v4.10-rc8, an application may trigger a BUG_ON in sctp_wait_for_sndbuf if the socket tx buffer is full, a thread is waiting on it to queue more data, and meanwhile another thread peels off the association being used by the first thread. (CVE-2017-5986)

Shmat allows mmap null page protection bypass :

The do_shmat function in ipc/shm.c in the Linux kernel, through 4.9.12, does not restrict the address calculated by a certain rounding operation. This allows privileged local users to map page zero and, consequently, bypass a protection mechanism that exists for the mmap system call. This is possible by making crafted shmget and shmat system calls in a privileged context. (CVE-2017-5669)

Solution

Run 'yum update kernel' to update your system.

See Also

https://alas.aws.amazon.com/ALAS-2017-814.html

Plugin Details

Severity: High

ID: 99418

File Name: ala_ALAS-2017-814.nasl

Version: 3.2

Type: local

Agent: unix

Published: 4/18/2017

Updated: 4/18/2018

Dependencies: ssh_get_info.nasl

Risk Information

VPR

Risk Factor: Medium

Score: 5.9

CVSS v2

Risk Factor: High

Base Score: 7.1

Vector: AV:N/AC:M/Au:N/C:N/I:N/A:C

CVSS v3

Risk Factor: High

Base Score: 7.8

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

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

Patch Publication Date: 4/6/2017

Reference Information

CVE: CVE-2017-5669, CVE-2017-5986, CVE-2017-6353

ALAS: 2017-814