Check Point Advisories

OpenSSL Encrypt-Then-Mac Renegotiation Denial of Service (CVE-2017-3733)

Vulnerability
Protection

Check Point Reference:	CPAI-2017-0237
Date Published:	22 Mar 2017
Severity:	Medium
Last Updated:	Sunday 07 May, 2017
Source:	OpenSSL
Industry Reference:	CVE-2017-3733
Protection Provided by:	Security Gateway R81, R80, R77, R75
Who is Vulnerable?	OpenSSL Project OpenSSL 1.1.x prior to 1.1.0e
Vulnerability Description	A denial of service vulnerability has been reported in OpenSSL. This vulnerability is due to improper handling of the Encrypt-Then-Mac extension during renegotiation. A remote attacker could exploit this vulnerability in an OpenSSL client or server application by sending crafted packets during renegotiation. Successful exploitation results in denial of service conditions on the affected service.

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 OpenSSL Encrypt-Then-Mac Renegotiation 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: SSL Enforcement Violation.
Attack Information: OpenSSL Encrypt-Then-Mac Renegotiation Denial of Service