COMMAND
loadmodule
SYSTEMS AFFECTED
SunOs 4.1.x and OpenWindows on all sun4 and Solbourne Computer,
Inc. architectures. The problem does not exists in Solaris 2.x,
Solaris x86, and sun3 architectures. (Openwindows was not
released for the sun3 architecture).
PROBLEM
There exists a vulnerability in /usr/etc/modload and
$OPENWIN/bin/loadmodule. This programs can be exploited to
execute a user's program using the effective UID of root. In
SunOS, the LD_* variables are ignored if the program is setuid.
The problem occurs when a setuid program calls a non-setuid
program, and passes the LD_* variable down. The non-setuid
program the interprets the LD_* variables, and faithfully loads
your trojan shared library or module. This is the case with the
'login', 'su' and 'sendmail' LD_* bugs.
SOLUTION
Apply the apropriate Sun patch. For loadmodule the patch is
100448-02, and for modload it is 101200-02. Solbourne systems do
not support the "loadmodule" functionality. This vulnerability
can be fixed on Solbourne systems by removing the setuid bit. The
modload program does not need to be replaced or changed.