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CERT Advisory: Unauthentic "Microsoft Corporation" Certificates

Mar 23, 2001, 14:11 (13 Talkback[s])
CERT Advisory CA-2001-04 Unauthentic "Microsoft Corporation" Certificates

   Original release date: March 22, 2001
   Last revised: March 22, 2001
   Source: CERT/CC

   A complete revision history can be found at the end of this file.

Systems Affected

   Systems whose users run code signed by Microsoft Corporation.

Overview

   On January 29 and 30, 2001, VeriSign, Inc. issued two certificates to
   an individual fraudulently claiming to be an employee of Microsoft
   Corporation. Any code signed by these certificates will appear to be
   legitimately signed by Microsoft when, in fact, it is not. Although
   users who try to run code signed with these certificates will
   generally be presented with a warning dialog, there will not be any
   obvious reason to believe that the certificate is not authentic.

I. Description

   Microsoft released a security bulletin on March 22, 2001, describing
   two certificates issued by VeriSign to an individual fraudulently
   claiming to be an employee of Microsoft. The full text of Microsoft's
   security bulletin is available from their web site at

       http://www.microsoft.com/technet/security/bulletin/MS01-017.asp

   Additional information about this issue is also available from
   VeriSign's web site:

       http://www.verisign.com/developer/notice/authenticode/index.html

   This issue presents a security risk because even a reasonably cautious
   user could be deceived into trusting the bogus certificates, since
   they appear to be from Microsoft. Once accepted, these certificates
   may allow an attacker to execute malicious code on the user's system.

   This problem is the result of a failure by the certificate authority
   to correctly authenticate the recipient of a certificate. Verisign has
   taken the appropriate action by revoking the certificates in question.
   However, this in itself is insufficient to prevent the malicious use
   of these certificates until a patch has been installed, because
   Internet Explorer does not check for such revocations automatically.

II. Impact

   Anyone with the private portions of the certificates can sign code
   such that it appears to have originated from Microsoft Corporation. If
   the user approves the execution of code signed by one of the bogus
   certificates, it can take any action on the system with the privileges
   of the user who approved the execution. The fake certificates can only
   be used for Authenticode signing.

III. Solution

Check "Microsoft Corporation" Certificates

   You can identify the fake certificates by checking the validity dates
   and serial numbers of the certificates. When prompted to authorize the
   execution of code signed by "Microsoft Corporation", press the "More
   Info" button to obtain additional information about the certificate
   used to sign the code.

   The fake certificates have the following description:

          Issued to: Microsoft Corporation
          Issued by: VeriSign Commercial Software Publishers CA
          Valid from 1/29/2001 to 1/30/2002
          Serial number is 1B51 90F7 3724 399C 9254 CD42 4637 996A

          Issued to: Microsoft Corporation
          Issued by: VeriSign Commercial Software Publishers CA
          Valid from 1/30/2001 to 1/31/2002
          Serial number is 750E 40FF 97F0 47ED F556 C708 4EB1 ABFD

   No legitimate certificates were issued to Microsoft between January 29
   and 30, 2001. Certificates with these initial validity dates or serial
   numbers should not be authorized to execute code.

   The certificate revocation list for the fake certificates can be found
   at

          http://crl.verisign.com/Class3SoftwarePublishers.crl

Apply a Patch from Your Vendor

   While there do not appear to be any patches available at this time
   that directly address this issue, Microsoft is working on producing
   patches that will ensure the invalid certificates are not used.

Appendix A. - Vendor Information

Microsoft Corporation

   Microsoft has published a security bulletin describing this issue at

          http://www.microsoft.com/technet/security/bulletin/MS01-017.asp

Netscape

   Netscape takes all security and privacy issues very seriously. The
   Netscape browser does not allow the execution of ActiveX controls,
   signed or unsigned, and therefore Netscape users are not vulnerable to
   exploits which rely on signed ActiveX. In the unlikely event that
   Netscape users are presented with signed content from Microsoft
   requesting enhanced privileges, Netscape users can protect themselves
   by denying permission to any such request.
   ______________________________________________________________________

   This document is available from:
   http://www.cert.org/advisories/CA-2001-04.html
   ______________________________________________________________________

CERT/CC Contact Information

   Email: cert@cert.org
          Phone: +1 412-268-7090 (24-hour hotline)
          Fax: +1 412-268-6989
          Postal address:
          CERT Coordination Center
          Software Engineering Institute
          Carnegie Mellon University
          Pittsburgh PA 15213-3890
          U.S.A.

   CERT personnel answer the hotline 08:00-20:00 EST(GMT-5) / EDT(GMT-4)
   Monday through Friday; they are on call for emergencies during other
   hours, on U.S. holidays, and on weekends.

Using encryption

   We strongly urge you to encrypt sensitive information sent by email.
   Our public PGP key is available from

   http://www.cert.org/CERT_PGP.key

   If you prefer to use DES, please call the CERT hotline for more
   information.

Getting security information

   CERT publications and other security information are available from
   our web site

   http://www.cert.org/

   To subscribe to the CERT mailing list for advisories and bulletins,
   send email to majordomo@cert.org. Please include in the body of your
   message

   subscribe cert-advisory

   * "CERT" and "CERT Coordination Center" are registered in the U.S.
   Patent and Trademark Office.
   ______________________________________________________________________

   NO WARRANTY
   Any material furnished by Carnegie Mellon University and the Software
   Engineering Institute is furnished on an "as is" basis. Carnegie
   Mellon University makes no warranties of any kind, either expressed or
   implied as to any matter including, but not limited to, warranty of
   fitness for a particular purpose or merchantability, exclusivity or
   results obtained from use of the material. Carnegie Mellon University
   does not make any warranty of any kind with respect to freedom from
   patent, trademark, or copyright infringement.
     _________________________________________________________________

   Conditions for use, disclaimers, and sponsorship information

   Copyright 2001 Carnegie Mellon University.

   Revision History
March 22, 2001: Initial release

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