Bug#598422: scilab: CVE-2010-3378: insecure library loading

[Raphael Geissert]

Package: scilab
Version: 5.2.2-4
Severity: grave
Tags: security
User: team at security.debian.org
Usertags: ldpath

Hello,

During a review of the Debian archive, I've found your package to
contain a script that can be abused by an attacker to execute arbitrary
code.

The vulnerability is introduced by an insecure change to
LD_LIBRARY_PATH, an environment variable used by ld.so(8) to look for
libraries on a directory other than the standard paths.

Vulnerable code follows:

/usr/bin/scilab-adv-cli line 280:
                    LD_LIBRARY_PATH="$JAVA_HOME/../Libraries:$LD_LIBRARY_PATH"
/usr/bin/scilab-adv-cli line 459:
		    LD_LIBRARY_PATH="$JRE_HOME/lib/$proc/:$JRE_HOME/lib/$proc/server/:$JRE_HOME/lib/$proc/native_threads/:$LD_LIBRARY_PATH"
/usr/bin/scilab-adv-cli line 518:
        LD_LIBRARY_PATH="$LD_LIBRARY_PATH:/sw/lib/"
/usr/bin/scilab-adv-cli line 534:
LD_LIBRARY_PATH=/usr/lib/scilab/:/usr/lib64/scilab/:$LD_LIBRARY_PATH
/usr/bin/scilab line 283:
                    LD_LIBRARY_PATH="$JAVA_HOME/../Libraries:$LD_LIBRARY_PATH"
/usr/bin/scilab line 462:
		    LD_LIBRARY_PATH="$JRE_HOME/lib/$proc/:$JRE_HOME/lib/$proc/server/:$JRE_HOME/lib/$proc/native_threads/:$LD_LIBRARY_PATH"
/usr/bin/scilab line 521:
        LD_LIBRARY_PATH="$LD_LIBRARY_PATH:/sw/lib/"
/usr/bin/scilab line 537:
LD_LIBRARY_PATH=/usr/lib/scilab/:/usr/lib64/scilab/:$LD_LIBRARY_PATH

When there's an empty item on the colon-separated list of
LD_LIBRARY_PATH, ld.so treats it as '.' (i.e. CWD/$PWD.)
If the given script is executed from a directory where a potential,
local, attacker can write files to, there's a chance to exploit this
bug.

This vulnerability has been assigned the CVE id CVE-2010-3378. Please make sure
you mention it when forwarding this report to upstream and when fixing
this bug (everywhere: upstream and here at Debian.)

[0] http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2010-3378
[1] http://security-tracker.debian.org/tracker/CVE-2010-3378

Sincerely,
Raphael Geissert