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                             Luigi Auriemma

Application:  Cytel Studio: StatXact / LogXact / CrossOver
              http://www.cytel.com/Software/StatXact.aspx
              http://www.cytel.com/Software/LogXact.aspx
              http://www.cytel.com/Software/Crossover.aspx
Versions:     <= 9.0.0
Platforms:    Windows
Bugs:         A] strings stack overflow
              B] rows integer overflow
              C] CYB USE stack overflow
Exploitation: file
Date:         02 Oct 2011
Author:       Luigi Auriemma
              e-mail: aluigi@autistici.org
              web:    aluigi.org


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1) Introduction
2) Bugs
3) The Code
4) Fix


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===============
1) Introduction
===============


From vendor's website:
"Cytel, the acknowledged leader in exact statistical methods, helped
pioneer exact methods for binary logistic regression and multinomial
regression."
"First introduced in 1987, LogXact is unequivocally the fastest and
most powerful logistic regression analysis software available today."
"With StatXact, Cytel's own powerful algorithms make exact inferences
by permuting the actually observed data, eliminating the need for
distributional assumptions."


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=======
2) Bugs
=======

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A] strings stack overflow
-------------------------

Buffer overflow during the copying of the strings in a stack buffer
of 256 bytes.


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B] rows integer overflow
------------------------

There is an integer overflow in the handling of the rows.
The number of rows (first element of the second line in the file) is
multiplied by the size of the elements (8 for floats, 4 for strings
and so on) and the allocated memory gets overflowed when the elements
are copied one by one.
At the moment I have not seen ways to exploit this vulnerability to
execute code so I report it just as reference.

Both the A and B problems are exploitable with the CY3 ("StatXact 5.0
data") and CYL ("LogXact data") files.


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C] CYB USE stack overflow
-------------------------

Stack overflow in the handling of the USE command of the CYB files.


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===========
3) The Code
===========


http://aluigi.org/poc/cytel_1.zip


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======
4) Fix
======


No fix.


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