BugTraq
PivX Advisory MK002B H&R Block TaxCut Information Disclosure Vulnerability Mar 13 2003 07:26AM
Mike Kristovich (mkristovich pivx com)


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Mike Kristovich, PivX Security Advisory MK#002B

Date: January 10, 2003

Application: H&R Block Tax Cut

Version: All versions up to current.

Bug: Information in saved Tax Returns discloses Social Security

Number, Full Information, and more..

Risk: Can allow for identity theft, information disclosure

Author: Mike Kristovich, Security Researcher, PivX Solutions, LLC

e-mail: mkristovich (at) pivx (dot) com [email concealed]

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Sections:

1) Introduction

2) Bug

3) Proof of concept code.

4) Fix

5) Philosophy

6) Closing comments..

7) Contact

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1) Introduction

According to the Jupiter report, 31 percent of online

households intend to file their taxes over the Web this

year, up from the 30 percent reported by the Internal

Revenue Service (IRS) last year. The IRS plans to receive

80 percent of all returns electronically by 2007.

Complaints about identity theft have risen 73 percent from

a year ago, according to a new report from the Federal Trade

Commission.

With the influx of e-tax filers and the rise in identity

theft PivX believes this vulnerability should be taken

quite seriously. Someone with a minimal set of computer skills

could locally or remotely obtain confidential information

on multitude of users.

TurboTax (Advisory #MK002A) and TaxCut (#MK002B) both

save their contents to the hard drive. These files are

unencrypted, and even with a simple text editor, you can

see all the information you would in the tax return.

These files can be accessed in any number of ways, but the

most likely way would be through unprotected windows shares.

Another key method to extract these files by means of a P2P

file sharing application such as Limewire, KaZaa, Morpheus,

etc etc. Many users have their P2P applications misconfigured

and this is supported by doing a quick search on the tax file

extension listed below. See the below KaZaa screenshot of a

local-range search for tax files. A full network search could

yeild thousands upon thousands of results.:

http://www.pivx.com/kristovich/images/kazaatax.jpg

The bottom line is:

- Be aware of what you are sharing to the public -

There are other ways files could be collected, such as

through a worm, an exploit, or a trojan horse.

H&R Block Tax Cut files are named with this extension:

".sbr" .. Decently small files < 8k usually.

and are usually located in a directory off the root of

the drive, such as "TaxCut02", under the subdirectory

"Program\TaxData"

A "hacked" H&R block computer could give an identity theft

hundreds of plaintext files full of information.

Example Screenshot:

[http://www.pivx.com/kristovich/images/taxcut.gif]

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2) Bug

Just a small insecurity can lead to a lot of information.

Tax Cut is pretty simple to view. Just load the file into

a text editor and you've got it all. Social Security #,

dependants SS#s, address, wages, etc.

Example Screenshot:

[http://www.pivx.com/kristovich/images/sbrfile.jpg]

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3) Proof-of-concept code

No proof of concept needed, just use a hex editor or text

editor as files are associated:

(.sbr) Text Editor

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4) Fix

* No response has yet been recieved from H&R Block. (1/10/2003)

* Second contact email sent on 1/29/2003.

* No response as of 3/04/2003.

The best solution is to move saved tax files to a more private place,

such as a CD-R. Even if a drive is not shared to the public, you may

still be at risk through other exploits or trojan horses.

As mentioned by Becky Worley in a TechTV article tuesday,

[http://www.techtv.com/news/security/story/0,24195,3420432,00.html]

Easy Crypto Deluxe is recommended to password protect your

sensitive data. You can download it here:

http://www.handybits.com/easycrypto.htm

Hopefully the company will create a fix for this problem.

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5) Philosophy

Full disclosure can lead to a quick fix, and prevent a problem before

it gets into the wrong hands.

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6) Closing comments..

In the electronic world, consider nothing secure. You should never

store this type of information on a live computer. Be careful.

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7) Contact

Any questions, comments, complaints, technical questions:

Mike Kristovich, Researcher

PivX Solutions, LLC

mkristovich (at) pivx (dot) com [email concealed]

Other Inquiries:

Geoff Shively, CHO

PivX Solutions, LLC

gshively (at) pivx (dot) com [email concealed]

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