PivX Advisory MK002A Intuit TurboTax Information Disclosure Vulnerability

Type securityvulns
Reporter Securityvulns
Modified 2003-03-13T00:00:00


Mike Kristovich, PivX Security Advisory MK#002A

Date: January 10, 2003

Application: Intuit TurboTax 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@pivx.com


1) Introduction 2) Bug 3) Proof of concept code. 4) Fix 5) Philosophy 6) Closing comments.. 7) Contact

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.

Many ISPs have blocked port 139 among others, but in newer versions of Windows, you may also be sharing on port 445. Port 445 is Microsoft Directory Service. A large number of tax files and the identities within can be harvested in a matter of minutes to hours.

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.

Intuit TurboTax files (.tax) are usually named this way:

"YYYY <Last> <First_I.> Tax Return.tax"

and the files are usually located off the root of the drive, in a directory such as "Tax02" "Tax01" "Tax99", etc.

2) Bug

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

For TurboTax, you can do a simple scan for the last name of the person, and closely following it, you'll see their social security number. Browse around that area of the file and you'll see their street address and more. If you use turbotax, load up one of your files in a binary editor and check it out for yourself.

3) Proof-of-concept code

No proof of concept needed, just use a hex editor or text editor as files are associated:

(.tax) Hex Editor

View Example Screenshot: http://www.pivx.com/kristovich/images/taxfile.jpg

4) Fix

Intuit has been contacted and is currently working on a solution.

They have informed us that they will now be encrypting files starting in the next version.

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

We thank Intuit for the extremely fast response on this one, keep up the good work!

5) Philosophy

Full disclosure can lead to a quick fix, and prevent a problem before it gets into the wrong hands.

6) Closing comments..

In the electronic world, consider nothing secure. You should never store this type of information on a live computer. Be careful.

7) Contact

Any questions, comments, complaints, technical questions:

Mike Kristovich, Researcher PivX Solutions, LLC mkristovich@pivx.com

Other Inquiries:

Geoff Shively, CHO PivX Solutions, LLC gshively@pivx.com