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Amazon Linux AMI : kernel (ALAS-2017-805)

critical Nessus Plugin ID 97557

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Synopsis

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

Description

A use-after-free flaw was found in the way the Linux kernel's Datagram Congestion Control Protocol (DCCP) implementation freed SKB (socket buffer) resources for a DCCP_PKT_REQUEST packet when the IPV6_RECVPKTINFO option is set on the socket. A local, unprivileged user could use this flaw to alter the kernel memory, allowing them to escalate their privileges on the system. (CVE-2017-6074)

A vulnerability was found in the Linux kernel. When file permissions are modified via chmod and the user is not in the owning group or capable of CAP_FSETID, the setgid bit is cleared in inode_change_ok().
Setting a POSIX ACL via setxattr sets the file permissions as well as the new ACL, but doesn't clear the setgid bit in a similar way; this allows to bypass the check in chmod. (CVE-2016-7097)

A vulnerability was found in the Linux kernel in 'tmpfs' file system.
When file permissions are modified via 'chmod' and the user is not in the owning group or capable of CAP_FSETID, the setgid bit is cleared in inode_change_ok(). Setting a POSIX ACL via 'setxattr' sets the file permissions as well as the new ACL, but doesn't clear the setgid bit in a similar way; this allows to bypass the check in 'chmod'.
(CVE-2017-5551)

An issue was found in the Linux kernel ipv6 implementation of GRE tunnels which allows a remote attacker to trigger an out-of-bounds access. (CVE-2017-5897)

It was discovered that 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)

A vulnerability was found in the Linux kernel where having malicious IP options present would cause the ipv4_pktinfo_prepare() function to drop/free the dst. This could result in a system crash or possible privilege escalation. (CVE-2017-5970)

A flaw was found in the Linux kernel's handling of packets with the URG flag. Applications using the splice() and tcp_splice_read() functionality can allow a remote attacker to force the kernel to enter a condition in which it can loop indefinitely. (CVE-2017-6214)

(Updated on 2017-03-21: CVE-2017-5970 was fixed in this release but was previously not part of this errata.)

(Updated on 2017-06-07: CVE-2017-6214 was fixed in this release but was previously not part of this errata.)

Solution

Run 'yum update kernel' to update your system. You will need to reboot your system in order for the new kernel to be running.

See Also

https://alas.aws.amazon.com/ALAS-2017-805.html

Plugin Details

Severity: Critical

ID: 97557

File Name: ala_ALAS-2017-805.nasl

Version: 3.9

Type: local

Agent: unix

Published: 3/7/2017

Updated: 10/27/2020

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

Risk Information

VPR

Risk Factor: Critical

Score: 9.0

CVSS v2

Risk Factor: High

Base Score: 7.5

Temporal Score: 6.2

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

CVSS v3

Risk Factor: Critical

Base Score: 9.8

Temporal Score: 9.1

Vector: CVSS:3.0/AV:N/AC:L/PR:N/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: 3/6/2017

Vulnerability Publication Date: 10/16/2016

Exploitable With

Core Impact

Reference Information

CVE: CVE-2016-7097, CVE-2017-5551, CVE-2017-5897, CVE-2017-5970, CVE-2017-5986, CVE-2017-6074, CVE-2017-6214

ALAS: 2017-805