From secnotif@MICROSOFT.COM Fri May 28 01:10:06 1999 From: Microsoft Product Security To: MICROSOFT_SECURITY@ANNOUNCE.MICROSOFT.COM Date: Thu, 27 May 1999 13:25:23 -0700 Subject: Microsoft Security Bulletin (MS99-017) The following is a Security Bulletin from the Microsoft Product Security Notification Service. Please do not reply to this message, as it was sent from an unattended mailbox. ******************************** Microsoft Security Bulletin (MS99-017) -------------------------------------- Patch Available for "RAS and RRAS Password" Vulnerability Originally Posted: May 27, 1999 Summary ======= Microsoft has released a patch that eliminates a vulnerability in the Microsoft (r) Windows NT (r) Remote Access Service (RAS) and Routing and Remote Access Service (RRAS) clients, in which a user's password is cached even if the user de-selects the "Save password" option. Issue ===== When the client software for Microsoft RAS or RRAS is used to dial into a server, a dialogue requests the user's userid and password for the server. On the same dialogue is a checkbox whose caption reads "Save password" and which is intended to provide the user with the option to cache their security credentials if desired. However, the implemented client functionality actually caches the user's credentials regardless of whether the checkbox is selected or de-selected. Cached security credentials, which include the password, are stored in the registry and protected by ACLs whose default values authorize only local administrators and the user to access them. Windows NT 4.0 Service Pack 4 also provides the ability to strongly encrypts the password data stored in the registry using the SYSKEY feature. While there are no reports of customers being adversely affected by this vulnerability, Microsoft is proactively releasing a patch that restores correct functionality to the password caching function. The patch should be applied to all machines that are used as RAS or RRAS clients. It is important to note that RRAS servers also can be used as RRAS clients, and any machines used in such a capacity should have the patch applied as well. Affected Software Versions ========================== - Microsoft Windows NT Workstation 4.0 - Microsoft Windows NT Server 4.0 - Microsoft Windows NT Server 4.0, Enterprise Edition What Microsoft is Doing ======================= Microsoft has released patches that fix the problem identified. The patches are available for download from the sites listed below in What Customers Should Do. Microsoft also has sent this security bulletin to customers subscribing to the Microsoft Product Security Notification Service. See http://www.microsoft.com/security/services/bulletin.asp for more information about this free customer service. Microsoft has published the following Knowledge Base (KB) article on this issue: - Microsoft Knowledge Base (KB) article Q230681, RAS Credentials Saved when "Save Password" Option Unchecked, http://support.microsoft.com/support/kb/articles/q230/6/81.asp - Microsoft Knowledge Base (KB) article Q233303, RRAS Credentials Saved when "Save Password" Option Unchecked, http://support.microsoft.com/support/kb/articles/q233/3/03.asp (Note: It might take 24 hours from the original posting of this bulletin for the KB article to be visible in the Web-based Knowledge Base.) What Customers Should Do ======================== Microsoft highly recommends that customers evaluate the degree of risk that this vulnerability poses to their systems and determine whether to download and install the patch. The patch can be found at: - RAS: ftp://ftp.microsoft.com/bussys/winnt/winnt-public /fixes/usa/nt40/Hotfixes-PostSP5/RASPassword-fix/ - RRAS: ftp://ftp.microsoft.com/bussys/winnt/winnt-public /fixes/usa/nt40/Hotfixes-PostSP5/RRASPassword-fix/ (Note: The URLs above have been wrapped for readability) More Information ================ Please see the following references for more information related to this issue. - Microsoft Security Bulletin MS99-017, Patch Available for "RAS and RRAS Password Caching" Vulnerability, (The Web-posted version of this bulletin), http://www.microsoft.com/security/bulletins/ms99-017.asp. - Microsoft Knowledge Base (KB) article Q230681, RAS Credentials Saved when "Save Password" Option Unchecked, http://support.microsoft.com/support/kb/articles/q230/6/81.asp. - Microsoft Knowledge Base (KB) article Q233303, RRAS Credentials Saved when "Save Password" Option Unchecked, http://support.microsoft.com/support/kb/articles/q233/3/03.asp Obtaining Support on this Issue =============================== If you require technical assistance with this issue, please contact Microsoft Technical Support. For information on contacting Microsoft Technical Support, please see http://support.microsoft.com/support/contact/default.asp. Revisions ========= - May 27, 1999: Bulletin Created. For additional security-related information about Microsoft products, please visit http://www.microsoft.com/security ---------------------------------------------------------------------- THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. 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