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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: This email address is being protected from spambots. You need JavaScript enabled to view it.
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,
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* "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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