Amazon Linux AMI : openssh (ALAS-2017-898)

high Nessus Plugin ID 103650

Synopsis

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

Description

A covert timing channel flaw was found in the way OpenSSH handled authentication of non-existent users. A remote unauthenticated attacker could possibly use this flaw to determine valid user names by measuring the timing of server responses. (CVE-2016-6210)

It was found that OpenSSH did not limit password lengths for password authentication. A remote unauthenticated attacker could use this flaw to temporarily trigger high CPU consumption in sshd by sending long passwords. (CVE-2016-6515)

It was found that ssh-agent could load PKCS#11 modules from arbitrary paths. An attacker having control of the forwarded agent-socket on the server, and the ability to write to the filesystem of the client host, could use this flaw to execute arbitrary code with the privileges of the user running ssh-agent. (CVE-2016-10009)

It was found that the host private key material could possibly leak to the privilege-separated child processes via re-allocated memory. An attacker able to compromise the privilege-separated process could therefore obtain the leaked key information. (CVE-2016-10011)

It was found that the boundary checks in the code implementing support for pre-authentication compression could have been optimized out by certain compilers. An attacker able to compromise the privilege-separated process could possibly use this flaw for further attacks against the privileged monitor process. (CVE-2016-10012)

Solution

Run 'yum update openssh' to update your system.

See Also

https://alas.aws.amazon.com/ALAS-2017-898.html

Plugin Details

Severity: High

ID: 103650

File Name: ala_ALAS-2017-898.nasl

Version: 3.3

Type: local

Agent: unix

Published: 10/4/2017

Updated: 4/10/2019

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

Risk Information

VPR

Risk Factor: Medium

Score: 5.9

CVSS v2

Risk Factor: High

Base Score: 7.8

Temporal Score: 6.1

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

CVSS v3

Risk Factor: High

Base Score: 7.8

Temporal Score: 7

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:P/RL:O/RC:C

Vulnerability Information

CPE: p-cpe:/a:amazon:linux:openssh-clients, p-cpe:/a:amazon:linux:openssh-cavs, p-cpe:/a:amazon:linux:openssh-keycat, p-cpe:/a:amazon:linux:pam_ssh_agent_auth, p-cpe:/a:amazon:linux:openssh-server, p-cpe:/a:amazon:linux:openssh-ldap, cpe:/o:amazon:linux, p-cpe:/a:amazon:linux:openssh, p-cpe:/a:amazon:linux:openssh-debuginfo

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: 10/3/2017

Reference Information

CVE: CVE-2016-10009, CVE-2016-10011, CVE-2016-10012, CVE-2016-6210, CVE-2016-6515

ALAS: 2017-898