Check Point Advisories

OpenSSL ClientHello signature_algorithms Extension Denial of Service (CVE-2015-0291)

Vulnerability
Protection

Check Point Reference:	CPAI-2015-0469
Date Published:	14 Apr 2015
Severity:	High
Last Updated:	Tuesday 21 April, 2015
Source:	OpenSSL0150319 secadv_20150319
Industry Reference:	CVE-2015-0291
Protection Provided by:	Security Gateway R81, R80, R77, R75
Who is Vulnerable?	OpenSSL Project OpenSSL 1.0.2
Vulnerability Description	A denial of service vulnerability exists in OpenSSL. The vulnerability is due to a null pointer dereference when an OpenSSL server application, during renegotiation, receives and processes an invalid signature_algorithms extension in a Client Hello handshake message. A remote, unauthenticated attacker can exploit this vulnerability by sending a crafted TLS 1.2 message during renegotiation. Successful exploitation will cause the server application to crash, resulting in a denial-of-service condition.

Protection Overview

This protection will detect and block 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 ClientHello signature_algorithms Extension 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: OpenSSL Enforcement Violation.
Attack Information: OpenSSL ClientHello signature_algorithms Extension Denial of Service