PT-2015-5436 · Microsoft · Windows 8+9

Published 2015-05-12 · Updated 2019-05-15 · CVE-2015-1716

Positive Technologies (AI Summary)

CVSS v2.0

5.0

Medium

Base vector

AV:N/AC:L/Au:N/C:P/I:N/A:N

Name of the Vulnerable Software and Affected Versions Microsoft Windows Server 2003 SP2 Microsoft Windows Vista SP2 Microsoft Windows Server 2008 SP2 and R2 SP1 Microsoft Windows 7 SP1 Microsoft Windows 8 Microsoft Windows 8.1 Microsoft Windows Server 2012 Gold and R2 Microsoft Windows RT Gold and 8.1

Description The issue arises from the improper restriction of Diffie-Hellman Ephemeral (DHE) key lengths in Schannel, making it easier for remote attackers to defeat cryptographic protection mechanisms. This is due to the allowance of weak DHE key lengths, specifically 512 bits, in encrypted TLS sessions, which makes DHE key exchanges weak and vulnerable to various attacks.

Recommendations For Microsoft Windows Server 2003 SP2, update to a version that properly restricts DHE key lengths. For Microsoft Windows Vista SP2, update to a version that properly restricts DHE key lengths. For Microsoft Windows Server 2008 SP2 and R2 SP1, update to a version that properly restricts DHE key lengths. For Microsoft Windows 7 SP1, update to a version that properly restricts DHE key lengths. For Microsoft Windows 8, update to a version that properly restricts DHE key lengths. For Microsoft Windows 8.1, update to a version that properly restricts DHE key lengths. For Microsoft Windows Server 2012 Gold and R2, update to a version that properly restricts DHE key lengths. For Microsoft Windows RT Gold and 8.1, update to a version that properly restricts DHE key lengths. As a temporary workaround, consider disabling the use of 512-bit DHE keys in Schannel until a patch is available.

Fix

Information Disclosure

Weakness Enumeration

CWE-200

Related Identifiers

CVE-2015-1716

Affected Products

Schannel

Windows

Windows 7

Windows 8

Windows 8.1

Windows Rt

Windows Server 2003

Windows Server 2008

Windows Server 2012

Windows Vista

References · 6

• http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-1716 · Security Note
• https://docs.microsoft.com/en-us/security-updates/securitybulletins/2015/ms15-055 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2015-1716 · Security Note
• http://technet.microsoft.com/security/bulletin/ms15-055 · Note
• http://securityfocus.com/bid/74489 · Note
• http://securitytracker.com/id/1032283 · Note