Mathematica8.0.4 on Linux /tmp/MathLink vulnerability

The problem reported for Mathematica became worse at version 8.0.4,
present for the command-line interface "math" also.

Cheers,

Paul Szabo [email protected] http://www.maths.usyd.edu.au/u/psz/
School of Mathematics and Statistics University of Sydney Australia

http://lists.grok.org.uk/pipermail/full-disclosure/2010-May/074548.html
http://www.securityfocus.com/archive/1/511298
http://www.securityfocus.com/bid/40169

Paraphrasing what I wrote on 14 May 2010:

"Mathematica is the world's ultimate application for computations…"
http://www.wolfram.com/products/

Mathematica on Linux uses the /tmp/MathLink directory in insecure ways.
Mathematica creates or re-uses an existing /tmp/MathLink directory, and
overwrites files within and follows symlinks. This type of behaviour is
"known unsafe" on multi-user machines e.g. University login servers.
As a classic example of a symlink attack, if an "attacker" uses:

mkdir /tmp/MathLink; ln -s /home/victim/.bashrc /tmp/MathLink/.shmsrec

then when the victim runs Mathematica his ~/.bashrc will be clobbered.
New files are created world-writable, allowing a complete compromise of
the user account by linking to ~/.bash_logout . (If root ever uses
Mathematica then the damage is greater.)

There is no workaround: the command-line math interface is also unsafe.

Notified [email protected] on 7 May 2010, was assigned [TS 16194].