__________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Center ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN Microsoft Authentication Error in SMTP Service [Microsoft Security Bulletin MS01-037] July 6, 2001 21:00 GMT Number L-107 ______________________________________________________________________________ PROBLEM: An SMTP service installs by default as part of Windows 2000 server products, and can be selected for installation on Windows 2000 Professional. A vulnerability results because of a flaw in the authentication process used by the service. PLATFORM: Microsoft Windows 2000 DAMAGE: The vulnerability could allow an unauthorized user to successfully authenticate to the service using incorrect credentials. The unauthorized user could gain user-level privileges on the SMTP service. SOLUTION: Apply the patch provided by Microsoft. ______________________________________________________________________________ VULNERABILITY The risk is LOW. The most likely purpose in exploiting the ASSESSMENT: vulnerability would be to perform mail relaying via the server. ______________________________________________________________________________ [****** Start Microsoft Security Bulletin ******] ------------------------------------------------------------------------------ Title: Authentication Error in SMTP Service Could Allow Mail Relaying Date: 05 July, 2001 Software: Windows 2000 Impact: Mail Relaying Bulletin: MS01-037 Microsoft encourages customers to review the Security Bulletin at: http://www.microsoft.com/technet/security/bulletin/MS01-037.asp. ------------------------------------------------------------------------------ Issue: ====== An SMTP service installs by default as part of Windows 2000 server products, and can be selected for installation on Windows 2000 Professional. A vulnerability results because of a flaw in the authentication process used by the service. The vulnerability could allow an unauthorized user to successfully authenticate to the service using incorrect credentials. An attacker who exploited the vulnerability could gain user-level privileges on the SMTP service, thereby enabling the attacker to use the service but not to administer it. The most likely purpose in exploiting the vulnerability would be to perform mail relaying via the server. Mitigating Factors: ==================== - Exchange servers -- even when run on Windows 2000 -- are not affected by this vulnerability. - Best practices recommend disabling unneeded services. If the SMTP service has been disabled, the vulnerability could not be exploited. - The vulnerability only affects stand-alone machines, not domain members. - Proper firewalling could prevent Internet-based attacks by blocking port 25 on servers that do not specifically need to accept SMTP traffic. Patch Availability: =================== - A patch is available to fix this vulnerability. Please read the Security Bulletin http://www.microsoft.com/technet/security/bulletin/ms01-037.asp for information on obtaining this patch. Acknowledgment: =============== - Joao Gouveia (tharbad@kaotik.org) -------------------------------------------------------------------------------- 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 Security Bulletin ******] _______________________________________________________________________________ CIAC wishes to acknowledge the contributions of Microsoft for the information contained in this bulletin. _______________________________________________________________________________ CIAC, the Computer Incident Advisory Center, 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. 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