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Re: Security Advisory - MyTaxexpress 2003
From: HCTITS Security Division <security () humancentrictech com>
Date: 27 Mar 2003 10:40:31 -0500

Did this guy miss the discussion about this very issue like, two weeks
ago?

I think the ultimate resolution of that discussion was that users are
lazy and stupid ("uninformed"), not likely to change defaults or be
savvy enough to use third-party encryption software, much less be
inclined to have to engage in that extra step.

There comes a point when we must wash our hands of the matter and leave
the user's security up to the user.  Inform them, yes, but leave them to
their own informed peril.

It sounds like most tax software does not encrypt personal data and
stores it in predictable locations.  I think a better tack on this
matter is to take steps to prevent the data from being accessible to
outside attackers.  Inform users how to disable the insecure default
shares that some OSes create and how to protect their computers from
many data-compromising vulnerabilities.  For example, "My Documents"
shouldn't be allowed to be accessible from outside anyway.

Or we could all do our taxes on paper, hand-deliver them to their
respective agents, keep our record copies in 6-inch hardened-steel
glass-packed (remember The Score?) fireproof safes, and crosscut-shred,
bleach, and burn any other paperwork with sensitive information.  

Regards,
~Brian


On Tue, 2003-03-25 at 14:46, Nathan Wosnack wrote:


Original Advisory: Tuesday, March 25, 2003

Severity: Medium - High

Description: Unencrypted tax-return information saved in C:\My Documents 
by default can pose security risks, and may disclose financial/personal 
information to the Internet via peer-to-peer (P2P) networks.

Version: Tested on the version released March 20, 2003

Authors: David Coomber and Nathan Wosnack were involved in the research 
and development.

Tax Software Background:

MyTaxexpress 2003 is a CCRA (Canada Customs and Revenue Agency) certified 
GUI application developed by ExpressInfo Software that allows Canadian tax 
payers located in Alberta, British Columbia, and Ontario to work through 
their tax returns and file them electronically using a tax filing system 
known as NETFILE.

Description of the problem:

If you decide to save your return, your personal information is saved to 
your computer unencrypted in the directory C:\My Documents by default with 
a *.ret extension. The problem with this is two-fold; if someone is able 
to access this file, then all they would need to do is open it with a text 
editor such as Notepad to reveal personal information. The personal 
information disclosed includes your full name, your address, your social 
insurance number, your earnings, spending claims, where you work, etc. 
Saving your tax files in C:\My Documents makes it easier to get a hold of 
since many Microsoft Windows users share C:\My Documents when using P2P 
programs without understanding the consequences. Also, Many P2P file-
sharing networks have been known to share the C:\My Documents folder. One 
such example of a file sharing program that does this is a program 
called 'Kazaa' (with K++ extensions). With a simple query on Kazaa, 
looking up file names such as 'taxes 2003.ret', 'taxes.ret', one could 
gather large amounts of data on unsuspecting users that have C:\My 
Documents shared.

Recommendations:

Due to the fact that MyTaxexpress does not encrypt your tax return when 
saved to disk, and stores it in C:\My Documents by default, the risk of 
having personal financial information stolen and used for illegal purposes 
is high. In order to protect this financial information from disclosure 
and misuse, we recommend saving your returns in a different directory and 
encrypting your returns (and all other personal information) with a strong 
encryption program such as Blowfish for Windows(1) or similar.

Related Links:

http://www.pivx.com/ - Related advisories focusing on United States tax 
software.

http://www.hypervivid.com/ - Information, Telecom and Wireless Security 
Consulting Firm.

Vendor Contact:

http://www.mytaxexpress.com/ - ExpressInfo software.

Have any questions or comments?
e-mail: advisories () hypervivid com

Copyright © 2003, Hypervivid Solutions Incorporated. All Rights Reserved. 
(1) Note: We are not affiliated with any products or services mentioned on 
this page, we provide the links solely as a convenience to the reader.



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