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

High Nessus Plugin ID 103650


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


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)


Run 'yum update openssh' to update your system.

See Also

Plugin Details

Severity: High

ID: 103650

File Name: ala_ALAS-2017-898.nasl

Version: 3.3

Type: local

Agent: unix

Published: 2017/10/04

Updated: 2019/04/10

Dependencies: 12634

Risk Information

Risk Factor: High

CVSS v2.0

Base Score: 7.8

Temporal Score: 6.1

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

Temporal Vector: CVSS2#E:POC/RL:OF/RC:C

CVSS v3.0

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, p-cpe:/a:amazon:linux:openssh-cavs, p-cpe:/a:amazon:linux:openssh-clients, p-cpe:/a:amazon:linux:openssh-debuginfo, p-cpe:/a:amazon:linux:openssh-keycat, p-cpe:/a:amazon:linux:openssh-ldap, p-cpe:/a:amazon:linux:openssh-server, p-cpe:/a:amazon:linux:pam_ssh_agent_auth, 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: 2017/10/03

Reference Information

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

ALAS: 2017-898