Executive Summary

Title Vulnerability in Schannel Could Allow Information Disclosure (3061518)
Name MS15-055 First vendor Publication 2015-05-12
Vendor Microsoft Last vendor Modification 2015-05-12
Severity (Vendor) Important Revision 1.0

Security-Database Scoring CVSS v3

Cvss vector : N/A
Overall CVSS Score NA
Base Score NA Environmental Score NA
impact SubScore NA Temporal Score NA
Exploitabality Sub Score NA
Calculate full CVSS 3.0 Vectors scores

Security-Database Scoring CVSS v2

Cvss vector : (AV:N/AC:L/Au:N/C:P/I:N/A:N)
Cvss Base Score 5 Attack Range Network
Cvss Impact Score 2.9 Attack Complexity Low
Cvss Expoit Score 10 Authentication None Required
Calculate full CVSS 2.0 Vectors scores


Severity Rating: Important
Revision Note: V1.0 (May 12, 2015): Bulletin published.
Summary: This security update resolves a vulnerability in Microsoft Windows. The vulnerability could allow information disclosure when Secure Channel (Schannel) allows the use of a weak Diffie-Hellman ephemeral (DFE) key length of 512 bits in an encrypted TLS session. Allowing 512-bit DHE keys makes DHE key exchanges weak and vulnerable to various attacks. A server needs to support 512-bit DHE key lengths for an attack to be successful; the minimum allowable DHE key length in default configurations of Windows servers is 1024 bits.

Original Source

Url : https://technet.microsoft.com/en-us/library/security/MS15-055

CWE : Common Weakness Enumeration

% Id Name
100 % CWE-200 Information Exposure

OVAL Definitions

Definition Id: oval:org.mitre.oval:def:28672
Oval ID: oval:org.mitre.oval:def:28672
Title: Schannel information disclosure vulnerability - CVE-2015-1716 (MS15-055)
Description: Schannel in Microsoft Windows Server 2003 SP2, Windows Vista SP2, Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8, Windows 8.1, Windows Server 2012 Gold and R2, and Windows RT Gold and 8.1 does not properly restrict Diffie-Hellman Ephemeral (DHE) key lengths, which makes it easier for remote attackers to defeat cryptographic protection mechanisms via unspecified vectors, aka "Schannel Information Disclosure Vulnerability."
Family: windows Class: vulnerability
Reference(s): CVE-2015-1716
Version: 3
Platform(s): Microsoft Windows 7
Microsoft Windows 8
Microsoft Windows 8.1
Microsoft Windows Server 2003
Microsoft Windows Server 2008
Microsoft Windows Server 2012
Microsoft Windows Server 2012 R2
Microsoft Windows Vista
Microsoft Windows Server 2008 R2
Definition Synopsis:

CPE : Common Platform Enumeration

Os 1
Os 1
Os 1
Os 1
Os 1
Os 1
Os 3
Os 2
Os 1

Information Assurance Vulnerability Management (IAVM)

Date Description
2015-05-14 IAVM : 2015-A-0111 - Microsoft SChannel Information Disclosure Vulnerability (MS15-055)
Severity : Category I - VMSKEY : V0060659

Nessus® Vulnerability Scanner

Date Description
2015-05-12 Name : The remote Windows host is affected by an information disclosure vulnerability.
File : smb_nt_ms15-055.nasl - Type : ACT_GATHER_INFO

Alert History

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Date Informations
2015-10-18 17:26:34
  • Multiple Updates
2015-05-14 00:28:50
  • Multiple Updates
2015-05-13 17:29:43
  • Multiple Updates
2015-05-13 13:28:09
  • Multiple Updates
2015-05-12 21:30:31
  • Multiple Updates
2015-05-12 21:17:20
  • First insertion