Solaris xscreensaver log Privilege Escalation

This module exploits a vulnerability in `xscreensaver` versions
since 5.06 on unpatched Solaris 11 systems which allows users
to gain root privileges.

`xscreensaver` allows users to create a user-owned file at any
location on the filesystem using the `-log` command line argument
introduced in version 5.06.

This module uses `xscreensaver` to create a log file in `/usr/lib/secure/`,
overwrites the log file with a shared object, and executes the shared
object using the `LD_PRELOAD` environment variable.

This module has been tested successfully on:

xscreensaver version 5.15 on Solaris 11.1 (x86); and
xscreensaver version 5.15 on Solaris 11.3 (x86).