#2009-010 mimeTeX and mathTeX buffer overflows and command injection

Description:

The mimeTeX and mathTeX CGIs are widely used helper executables that allow
mathematical equation rendering in the form of images. Both applications suffer
from several buffer overflows as well as command injection which result in
remote code execution.

The mimeTeX application suffers from several stack-based buffer overflows which
can be remotely triggered by passing oversized TeX expressions.  Additionally
the \environ, \input and \counter directives may not be suitable for exposure
to commands from the Internet.

Similarly the mathTeX application does not perform sufficient input
sanitization and allows untrusted input, passed via HTTP query strings, to be
used as command arguments allowing command injection. Additionally it suffers
from several stack-based overflows as well as insecure temporary file handling.

Affected version:

Unfortunately mimeTeX and mathTex are provided without version numbers by the
maintainer, who releases version-less zip archives. It is therefore impossible
to provide affected version numbers.

Fixed version:

At the release time for this advisory both versions available on the maintainer
website fix the overflow and injection issues.

mimeTeX, mimetex.zip (2009/07/13)

mathTeX, mathtex.zip (2009/07/13)

Credit: vulnerability report received from Chris Evans <cevans [at] google
        [dot] com> (mimetex) and Damien Miller <djm [at] google [dot] com>
        (mathtex), Google Security Team.

CVE: CVE-2009-1382 (mimetex), CVE-2009-1383 (mathtex)

Timeline:

2009-05-22: vulnerability report received
2009-05-25: contacted mimetex/mathtex maintainer
2009-05-25: maintainer publicly discloses report contents
2009-05-26: contacted affected vendors
2009-05-26: maintainer provides updated packages
2009-05-26: assigned CVEs
2009-05-26: reporters indicate that the updated packages do not fix all
            the issues
2009-05-29: reporters find additional overflows in updated packages
2009-06-01: maintainer contacted with updated report
2009-07-09: reporters confirm that updated packages fixing the reported
            issues are available
2009-07-13: advisory release

References:
http://scary.beasts.org/security/CESA-2009-009.html
http://groups.google.com/group/comp.text.tex/browse_thread/thread/5d56d3d744351578

Permalink:
http://www.ocert.org/advisories/ocert-2009-010.html

-- 
Andrea Barisani |                Founder & Project Coordinator
          oCERT | Open Source Computer Emergency Response Team

<lcars@ocert.org>                         http://www.ocert.org
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