Check Point Advisories

OpenSSH kex_input_kexinit Denial of Service (CVE-2016-8858)

Vulnerability
Protection

Check Point Reference:	CPAI-2017-0307
Date Published:	23 Apr 2017
Severity:	High
Last Updated:	Sunday 30 April, 2017
Source:	OpenSSH
Industry Reference:	CVE-2016-8858
Protection Provided by:	Security Gateway R81, R80, R77, R75
Who is Vulnerable?	OpenSSH OpenSSH prior to revision 1.127 OpenSSH OpenSSH portable prior to version 7.4p1
Vulnerability Description	A denial of service vulnerability has been reported in OpenSSH. The vulnerability is due to improper implementation of the kex_input_kexinit function in the kex module allowing the function to be repeated after receipt of a message. A remote attacker could exploit this vulnerability by sending maliciously crafted request to the server during the key-exchange process.

Protection Overview

This protection detects attempts to exploit this vulnerability.

In order for the protection to be activated, update your Security Gateway product to the latest IPS update. For information on how to update IPS, go to SBP-2006-05, click on Protection tab and select the version of your choice.

Security Gateway R80 / R77 / R75

In the IPS tab, click Protections and find the OpenSSH kex_input_kexinit Denial of Service protection using the Search tool and Edit the protection's settings.
Install policy on all Security Gateways.

This protection's log will contain the following information:

Attack Name: SSH Protection Violation.
Attack Information: OpenSSH kex_input_kexinit Denial of Service