Check Point Advisories

TLS DHE_EXPORT Information Disclosure (MS15-055; CVE-2015-4000; CVE-2015-1716)

Check Point Reference: CPAI-2015-0802
Date Published: 7 Jul 2015
Severity: High
Last Updated: 15 Nov 2017
Source: Microsoft Security Bulletin MS15-055
Industry Reference:CVE-2015-4000
Protection Provided by:

Security Gateway
R80, R77, R76, R75

Who is Vulnerable? Microsoft Windows 7
Microsoft Windows 8
Microsoft Windows 8.1
Microsoft Windows RT
Microsoft Windows RT 8.1
Microsoft Windows Server 2008
Microsoft Windows Server 2008 R2
Microsoft Windows Server 2012
Microsoft Windows Server 2012 R2
OpenSSL Project OpenSSL prior to 1.0.1n
OpenSSL Project OpenSSL prior to 1.0.2b
Vulnerability Description An information disclosure vulnerability exists in multiple implementations of TLS 1.2 and earlier, when Ephemeral Diffie-Hellman cipher suites including their EXPORT versions are used. It is possible to downgrade a DHE cipher to a DHE_EXPORT cipher, which can be broken, and thereby perform a man-in-the-middle attack. This vulnerability is popularly called the 'Logjam' TLS attack. Successful exploitation would allow the attacker to decrypt the traffic and obtain or modify sensitive information.
Update/Patch AvaliableApply patches from: MS15-055

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 / R76 / R75

  1. In the IPS tab, click Protections and find the TLS DHE_EXPORT Information Disclosure (MS15-055) protection using the Search tool and Edit the protection's settings.
  2. Install policy on all modules.

This protection's log will contain the following information:

Attack Name:  SSL Enforcement Violation.
Attack Information:  TLS DHE_EXPORT Information Disclosure (MS15-055)