Check Point Advisories

NTP Servers Symmetric Association Authentication Bypass (CVE-2015-7871)

Vulnerability
Protection

Check Point Reference:	CPAI-2015-1232
Date Published:	24 Oct 2015
Severity:	Critical
Last Updated:	Thursday 03 December, 2015
Source:
Industry Reference:	CVE-2015-7871
Protection Provided by:	Security Gateway R81, R80, R77, R75
Who is Vulnerable?	NTP Server versions < 4.2.8p3
Vulnerability Description	A logical flaw exists in NTP servers when handling certain crypto-NAK packets, allowing attackers to bypass the target server's authentication. A remote attacker can leverage this flaw by sending a specially crafted request, and manipulate the server system's time.

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 NTP Servers Symmetric Association Authentication Bypass 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: NTP Enforcement Violation.
Attack Information: NTP Servers Symmetric Association Authentication Bypass