-----BEGIN PGP SIGNED MESSAGE----- __________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Capability ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN Microsoft PPTP Security Vulnerabilities August 19, 1998 16:00 GMT Number I-087 ______________________________________________________________________________ PROBLEM: Microsoft has identified vulnerabilities in the Point-to-Point Tunneling Protocol (PPTP). PLATFORM: Microsoft Dialup Networking 1.2x and earlier on Windows 95. Microsoft Remote Access Services on Windows NT 4.0. Microsoft Routing and Remote Access Services on Windows NT Server 4.0. Microsoft Windows 98 Dialup Networking. DAMAGE: Dictionary attack against the LAN Manager authentication information. Password theft. PPTP server spoofing. Reuse of MPPE session keys. SOLUTION: Apply available patches. ______________________________________________________________________________ VULNERABILITY Risk is high. Exploitation of these vulnerabilities could allow ASSESSMENT: the capture of passwords or viewing the contents of encrypted sessions. ______________________________________________________________________________ [ Start Microsoft Corp. Advisory ] Microsoft Security Bulletin (MS98-012) - ------------------------------------------------------------------------------ Updates available for Security Vulnerabilities in Microsoft PPTP Originally Posted: August 18, 1998 Last Revised: August 18, 1998 Summary Microsoft has released a set of patches that fix several security issues with implementations of the Point-to-Point Tunneling Protocol (PPTP) used in Microsoft Virtual Private Networking (VPN) products. Customers using affected software listed below to secure communications over a public network (i.e. the Internet) should download and apply these patches as soon as possible. Customers who are not using PPTP for network security are not affected by this issue. Issue The Microsoft implementation of PPTP uses MS-CHAP for user authentication and Microsoft Point-to-Point Encryption (MPPE) to protect the confidentiality of user data. Potential vulnerabilities addressed by these updates include: Dictionary attack against the LAN Manager authentication information Password theft PPTP server spoofing Reuse of MPPE session keys While there have not been any reports of customers being adversely affected by these problems, Microsoft is releasing these patches to address the implied risks posed by these issues. Affected Software Versions The following software is affected by this vulnerability: Microsoft Dialup Networking 1.2x and earlier on Windows 95 Microsoft Remote Access Services on Windows NT 4.0 (both client and server) Microsoft Routing and Remote Access Services on Windows NT Server 4.0 Microsoft Windows 98 Dialup Networking What Microsoft is Doing On August 18th Microsoft released a set of patches that fix the problems identified. These patches are available for download by Windows NT, Windows 95 and Windows 98 customers from the Microsoft FTP site. Microsoft has sent this security bulletin to customers subscribing to the Microsoft Product Security Notification Service (see http://www.microsoft.com/security/bulletin.htm for more information about this free customer service). Microsoft has published the following Knowledge Base (KB) articles on this issue: Microsoft Knowledge Base (KB) article Q154091, Windows 95 Dial-Up Networking 1.3 Upgrade Release Notes http://support.microsoft.com/support/kb/articles/q154/0/91.asp Microsoft Knowledge Base (KB) article Q189594, RRAS Hotfix 3.0 http://support.microsoft.com/support/kb/articles/q189/5/94.asp Microsoft Knowledge Base (KB) article Q189595, Windows NT 4.0 PPTP Security Update http://support.microsoft.com/support/kb/articles/q189/5/95.asp Microsoft Knowledge Base (KB) article Q189771, Windows 98 PPTP Security Update http://support.microsoft.com/support/kb/articles/q189/7/71.asp What customers should do Microsoft highly recommends that users of affected software versions, listed in the "Affected Software Versions" section above, should download the appropriate patch. Complete URLs for each affected software version is given below. Windows NT 4.0 RAS Users Download the patch from: ftp://ftp.microsoft.com/bussys/winnt/winnt-public/fixes/usa/NT40/hotfixes- postSP3/pptp3-fix/ Windows NT 4.0 RRAS Users Download the patch from: ftp://ftp.microsoft.com/bussys/winnt/winnt-public/fixes/usa/NT40/hotfixes- postSP3/rras30-fix/ Windows 95 Users Download the patch from: ftp://ftp.microsoft.com/softlib/mslfiles/msdun13.exe Windows 98 Users Download the patch from: ftp://ftp.microsoft.com/softlib/mslfiles/dun40.exe Strong Encryption Versions (128-bit) Customers in the United States and Canada can download the strong encryption versions of these updates from: http://mssecure.www.conxion.com/cgi-bin/ntitar.pl More Information Please see the following references for more information related to this issue. Microsoft Security Bulletin MS98-012, Updates available for Security Vulnerabilities in Microsoft PPTP, (the Web posted version of this bulletin), http://www.microsoft.com/security/bulletins/ms98-012.htm Microsoft Knowledge Base (KB) article Q154091, Windows 95 Dial-Up Networking 1.3 Upgrade Release Notes http://support.microsoft.com/support/kb/articles/q154/0/91.asp Microsoft Knowledge Base (KB) article Q189594, RRAS Hotfix 3.0 http://support.microsoft.com/support/kb/articles/q189/5/94.asp Microsoft Knowledge Base (KB) article Q189595, Windows NT 4.0 PPTP Security Update http://support.microsoft.com/support/kb/articles/q189/5/95.asp Microsoft Knowledge Base (KB) article Q189771, Windows 98 PPTP Security Update http://support.microsoft.com/support/kb/articles/q189/7/71.asp Revisions August 18, 1998: 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. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY. [ End Microsoft Corp. Advisory ] ______________________________________________________________________________ CIAC wishes to acknowledge the contributions of Microsoft Corp. for the information contained in this bulletin. ______________________________________________________________________________ CIAC, the Computer Incident Advisory Capability, is the computer security incident response team for the U.S. Department of Energy (DOE) and the emergency backup response team for the National Institutes of Health (NIH). CIAC is located at the Lawrence Livermore National Laboratory in Livermore, California. CIAC is also a founding member of FIRST, the Forum of Incident Response and Security Teams, a global organization established to foster cooperation and coordination among computer security teams worldwide. CIAC services are available to DOE, DOE contractors, and the NIH. CIAC can be contacted at: Voice: +1 925-422-8193 FAX: +1 925-423-8002 STU-III: +1 925-423-2604 E-mail: ciac@llnl.gov For emergencies and off-hour assistance, DOE, DOE contractor sites, and the NIH may contact CIAC 24-hours a day. During off hours (5PM - 8AM PST), call the CIAC voice number 925-422-8193 and leave a message, or call 800-759-7243 (800-SKY-PAGE) to send a Sky Page. CIAC has two Sky Page PIN numbers, the primary PIN number, 8550070, is for the CIAC duty person, and the secondary PIN number, 8550074 is for the CIAC Project Leader. Previous CIAC notices, anti-virus software, and other information are available from the CIAC Computer Security Archive. World Wide Web: http://www.ciac.org/ (or http://ciac.llnl.gov -- they're the same machine) Anonymous FTP: ftp.ciac.org (or ciac.llnl.gov -- they're the same machine) Modem access: +1 (925) 423-4753 (28.8K baud) +1 (925) 423-3331 (28.8K baud) CIAC has several self-subscribing mailing lists for electronic publications: 1. CIAC-BULLETIN for Advisories, highest priority - time critical information and Bulletins, important computer security information; 2. SPI-ANNOUNCE for official news about Security Profile Inspector (SPI) software updates, new features, distribution and availability; 3. SPI-NOTES, for discussion of problems and solutions regarding the use of SPI products. Our mailing lists are managed by a public domain software package called Majordomo, which ignores E-mail header subject lines. To subscribe (add yourself) to one of our mailing lists, send the following request as the E-mail message body, substituting ciac-bulletin, spi-announce OR spi-notes for list-name: E-mail to ciac-listproc@llnl.gov or majordomo@tholia.llnl.gov: subscribe list-name e.g., subscribe ciac-bulletin You will receive an acknowledgment email immediately with a confirmation that you will need to mail back to the addresses above, as per the instructions in the email. This is a partial protection to make sure you are really the one who asked to be signed up for the list in question. If you include the word 'help' in the body of an email to the above address, it will also send back an information file on how to subscribe/unsubscribe, get past issues of CIAC bulletins via email, etc. PLEASE NOTE: Many users outside of the DOE, ESnet, and NIH computing communities receive CIAC bulletins. If you are not part of these communities, please contact your agency's response team to report incidents. Your agency's team will coordinate with CIAC. The Forum of Incident Response and Security Teams (FIRST) is a world-wide organization. A list of FIRST member organizations and their constituencies can be obtained via WWW at http://www.first.org/. This document was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor the University of California nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial products, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation or favoring by the United States Government or the University of California. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or the University of California, and shall not be used for advertising or product endorsement purposes. LAST 10 CIAC BULLETINS ISSUED (Previous bulletins available from CIAC) I-077: Mime Name Vulnerability in Outlook and Messenger I-078: HP-UX ftp Security Vulnerability I-079: IBM AIX "sdrd" daemon Vulnerability I-080: Microsoft Exchange Denial of Service Attacks I-081: HP-UX & MPEix Predictive Vulnerability I-082: HP-UX Netscape Servers Vulnerability I-083: Eudora Pro E-Mail Attachment Vulnerability I-084: Cisco IOS Remote Router Crash I-085: Microsoft IE Upgrade Trojan Horse Program I-086: Cisco CRM Temporary File Vulnerability -----BEGIN PGP SIGNATURE----- Version: 4.0 Business Edition iQCVAwUBNdsZ6bnzJzdsy3QZAQGc/QP9HYsemLSasZwuaMP9idSZP7E0X1Le9k7u wmqglzleRTgRqBTv8G1JlcNVRS+0rjfHYYE4wZmDC8CegOJJoFphnAOVWqtIgvS+ hbQCYxZnotacSxvqNhqqEOqs1JpK2yQebkvOt8kZM0UILDAPdXEQz9CEAH/2LXF2 dg/Jucql4Oc= =Q9p0 -----END PGP SIGNATURE-----