@therealsaumil
@_ringzer0
debugging WITH EMUX
SAUMIL SHAH
@therealsaumil
7 JULY 2022
< BACK2
workshops`
ringzer¿
@therealsaumil
@_ringzer0
# WHO AM I
Saumil Shah
@therealsaumil
educating, entertaining
and exasperating
audiences since 1999
@therealsaumil
@_ringzer0
WHAT IS
ARM + MIPS IoT Emulation Framework
emux.exploitlab.net
@therealsaumil
@_ringzer0
What Is This Workshop About
An Introduction to debugging binaries on emulated targets
Using GDB + gdbserver for remote debugging
Hands-on examples
How EMUX makes the debugging process easy
@therealsaumil
@_ringzer0
EMUX docker container
HOST
EMUX DOCKER
launcher
EMULATED
TARGET ON
QEMU
emux-docker-shell
workspace
(shared
directory)
nweb
(target binary)
192.168.100.2
192.168.100.1
socat
80
20080
RINGZER0 HACKME
@therealsaumil
@_ringzer0
Concepts Covered
Functions of a Debugger
How does Remote Debugging work
EMUX's debugger wrappers
Advantages of using GEF
Debugging a webserver binary
Crash Dump Analysis
@therealsaumil
@_ringzer0
Functions of a Debugger
Inspect the target
Inspect the CPU state
Examine Memory
Control Process Execution
Analyse Crashes and Exceptions
Luxuries: Plugins, Macros, Logging
@therealsaumil
@_ringzer0
Remote Debugging - how it works
GDB multiarch
nweb
(target binary)
192.168.100.1
gdbserver :5000
--attach <PID>
(gdb) target remote 192.168.100.2:5000
(gdb) set sysroot target:/path/to/rootfs
(gdb) continue
REMOTE HOST
192.168.100.2
@therealsaumil
@_ringzer0
Remote Debugging - emuxgdb
emux-docker-shell
nweb
(target binary)
REMOTE HOST
192.168.100.1
gdbserver
$ emuxgdb nweb
(gdb)
" Automatically looks up the PID of the target
" Launches gdbserver on the remote host
" Launches gdb-multiarch locally
" Connects to remote gdbserver
" Sets sysroot
" Ready to debug!
192.168.100.2
@therealsaumil
@_ringzer0
Plain ol GDB -vs- new & shiny GEF
@therealsaumil
@_ringzer0
A few GDB/GEF commands
RECONNAISSANCE
vmmap [GEF] Display the process' memory layout
info target Information about the target being debugged (ELF binary)
info sharedlibrary Shared Libraries that are loaded with the binary
info functions List of functions that belong to the target binary
PROCESS EXECUTION
break Set a breakpoint
continue Resume process execution
rbreak Set multiple breakpoints using regular expressions
stepi / nexti Step Into / Next Instruction
CPU AND MEMORY
context [GEF] Better view of registers, stack, code, call stack, etc.
x Examine memory (many variations)
hexdump [GEF] When you want characters and bytes side by side
backtrace Display the call stack
info frame Inspect stack frames
disassemble Disassemble code
printf Formatted printing
LUXURIES
set logging Enable / Disable logging and redirect log output to a file
commands Execute multiple commands in sequence every time a breakpoint is reached
@therealsaumil
@_ringzer0
EMUX utilities
emuxps List processes running in the emulated device
emuxkill Terminate a process inside the emulated device
emuxmaps Remote process virtual memory layout
emuxgdb Attach gdb to a remote process in the emulated device
emuxnetstat Remote netstat
emuxhalt Shut down the emulated device
monitor Attach to QEMU monitor
@therealsaumil
@_ringzer0
SETTING UP!
@therealsaumil
@_ringzer0
Start EMUX
./run-emux-docker
:
:
[+] Setting up forwarded ports 20080:80,20443:443,28080:8080,24433:4433,9999:9999
[+] mapping port 20080 -> 192.168.100.2:80
[+] mapping port 20443 -> 192.168.100.2:443
[+] mapping port 28080 -> 192.168.100.2:8080
[+] mapping port 24433 -> 192.168.100.2:4433
[+] mapping port 9999 -> 192.168.100.2:9999
___ __ __ _ __ __
/ __| / | | | / / by Saumil Shah | The Exploit Laboratory
| __| |/| | |_| ) ( @therealsaumil | emux.exploitlab.net
___|_| |_____/_/_
[EMUX-DOCKER !] ~$
1. Start the EMUX Docker Container
@therealsaumil
@_ringzer0
Launch the target
2. Run launcher and boot into Damn Vulnerable ARM Router
[EMUX-DOCKER !] ~$ launcher
@therealsaumil
@_ringzer0
Start Userspace
./emux-docker-shell
[emux-docker !] ~$
3. Open a new terminal window and attach to emux-docker-shell
[emux-docker !] ~$ userspace
4. Run userspace
@therealsaumil
@_ringzer0
Enter the DVAR Console
5. Select "Enter the Damn Vulnerable ARM Router CONSOLE" option
@therealsaumil
@_ringzer0
Start nweb (our target binary)
Entering Damn Vulnerable ARM Router CONSOLE (/bin/sh)
[+] Logging enabled
[+] EMUX Debug log - /home/r0/workspace/logs/emuxdebug.log
[+] QEMU Console log - qemuconsole.log
[+] chroot /emux/DV-ARM/rootfs-arm /.emux/emuxshell
Script started, output log file is '/home/r0/workspace/logs/emuxdebug.log'.
BusyBox v1.23.2 (2021-10-14 18:26:48 IST) built-in shell (ash)
/ # nweb 80 /www/nweb/
6. Manually start the nweb web server from the Busybox prompt
./emux-docker-shell
[emux-docker !] ~$ curl http://192.168.100.2
<h1>Ringzer0 Hackme</h1>
7. Start another emux-docker-shell and test nweb
@therealsaumil
@_ringzer0
Grab the attack scripts!
[emux-docker !] ~$ cd workspace
[emux-docker !] ~/workspace$ wget https://saumil.net/tmp/attack1.py
--2022-07-07 14:12:48-- https://saumil.net/tmp/attack1.py
Resolving saumil.net (saumil.net)... 208.113.163.5
Connecting to saumil.net (saumil.net)|208.113.163.5|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 535 [text/plain]
Saving to: 'attack1.py'
attack1.py 100%[=======================>] 535 --.-KB/s in 0s
2022-07-07 14:12:50 (58.9 MB/s) - 'attack1.py' saved [535/535]
[emux-docker !] ~/workspace$ chmod +x attack1.py
8. From the emux-docker-shell grab the following attack scripts
@therealsaumil
@_ringzer0
HANDS ON
EMUXGDB
@therealsaumil
@_ringzer0
HERE BE THE GOODS
CODE: https://github.com/therealsaumil/emux
!-
ANNOUNCEMENTS: @therealsaumil
DOCS: https://emux.exploitlab.net/
@therealsaumil
@_ringzer0
ringzer¿
AUGUST 6-9
REGISTRATIONS OPEN
www.ringzer¿.training
THE ARM IoT
EXPLOIT LABORATORY
@therealsaumil
@_ringzer0
THANK YOU!
SAUMIL SHAH
@therealsaumil
7 JULY 2022
< BACK2
workshops`
ringzer¿

Debugging with EMUX - RIngzer0 BACK2WORKSHOPS

  • 1.
    @therealsaumil @_ringzer0 debugging WITH EMUX SAUMILSHAH @therealsaumil 7 JULY 2022 < BACK2 workshops` ringzer¿
  • 2.
    @therealsaumil @_ringzer0 # WHO AMI Saumil Shah @therealsaumil educating, entertaining and exasperating audiences since 1999
  • 3.
    @therealsaumil @_ringzer0 WHAT IS ARM +MIPS IoT Emulation Framework emux.exploitlab.net
  • 4.
    @therealsaumil @_ringzer0 What Is ThisWorkshop About An Introduction to debugging binaries on emulated targets Using GDB + gdbserver for remote debugging Hands-on examples How EMUX makes the debugging process easy
  • 5.
    @therealsaumil @_ringzer0 EMUX docker container HOST EMUXDOCKER launcher EMULATED TARGET ON QEMU emux-docker-shell workspace (shared directory) nweb (target binary) 192.168.100.2 192.168.100.1 socat 80 20080 RINGZER0 HACKME
  • 6.
    @therealsaumil @_ringzer0 Concepts Covered Functions ofa Debugger How does Remote Debugging work EMUX's debugger wrappers Advantages of using GEF Debugging a webserver binary Crash Dump Analysis
  • 7.
    @therealsaumil @_ringzer0 Functions of aDebugger Inspect the target Inspect the CPU state Examine Memory Control Process Execution Analyse Crashes and Exceptions Luxuries: Plugins, Macros, Logging
  • 8.
    @therealsaumil @_ringzer0 Remote Debugging -how it works GDB multiarch nweb (target binary) 192.168.100.1 gdbserver :5000 --attach <PID> (gdb) target remote 192.168.100.2:5000 (gdb) set sysroot target:/path/to/rootfs (gdb) continue REMOTE HOST 192.168.100.2
  • 9.
    @therealsaumil @_ringzer0 Remote Debugging -emuxgdb emux-docker-shell nweb (target binary) REMOTE HOST 192.168.100.1 gdbserver $ emuxgdb nweb (gdb) " Automatically looks up the PID of the target " Launches gdbserver on the remote host " Launches gdb-multiarch locally " Connects to remote gdbserver " Sets sysroot " Ready to debug! 192.168.100.2
  • 10.
  • 11.
    @therealsaumil @_ringzer0 A few GDB/GEFcommands RECONNAISSANCE vmmap [GEF] Display the process' memory layout info target Information about the target being debugged (ELF binary) info sharedlibrary Shared Libraries that are loaded with the binary info functions List of functions that belong to the target binary PROCESS EXECUTION break Set a breakpoint continue Resume process execution rbreak Set multiple breakpoints using regular expressions stepi / nexti Step Into / Next Instruction CPU AND MEMORY context [GEF] Better view of registers, stack, code, call stack, etc. x Examine memory (many variations) hexdump [GEF] When you want characters and bytes side by side backtrace Display the call stack info frame Inspect stack frames disassemble Disassemble code printf Formatted printing LUXURIES set logging Enable / Disable logging and redirect log output to a file commands Execute multiple commands in sequence every time a breakpoint is reached
  • 12.
    @therealsaumil @_ringzer0 EMUX utilities emuxps Listprocesses running in the emulated device emuxkill Terminate a process inside the emulated device emuxmaps Remote process virtual memory layout emuxgdb Attach gdb to a remote process in the emulated device emuxnetstat Remote netstat emuxhalt Shut down the emulated device monitor Attach to QEMU monitor
  • 13.
  • 14.
    @therealsaumil @_ringzer0 Start EMUX ./run-emux-docker : : [+] Settingup forwarded ports 20080:80,20443:443,28080:8080,24433:4433,9999:9999 [+] mapping port 20080 -> 192.168.100.2:80 [+] mapping port 20443 -> 192.168.100.2:443 [+] mapping port 28080 -> 192.168.100.2:8080 [+] mapping port 24433 -> 192.168.100.2:4433 [+] mapping port 9999 -> 192.168.100.2:9999 ___ __ __ _ __ __ / __| / | | | / / by Saumil Shah | The Exploit Laboratory | __| |/| | |_| ) ( @therealsaumil | emux.exploitlab.net ___|_| |_____/_/_ [EMUX-DOCKER !] ~$ 1. Start the EMUX Docker Container
  • 15.
    @therealsaumil @_ringzer0 Launch the target 2.Run launcher and boot into Damn Vulnerable ARM Router [EMUX-DOCKER !] ~$ launcher
  • 16.
    @therealsaumil @_ringzer0 Start Userspace ./emux-docker-shell [emux-docker !]~$ 3. Open a new terminal window and attach to emux-docker-shell [emux-docker !] ~$ userspace 4. Run userspace
  • 17.
    @therealsaumil @_ringzer0 Enter the DVARConsole 5. Select "Enter the Damn Vulnerable ARM Router CONSOLE" option
  • 18.
    @therealsaumil @_ringzer0 Start nweb (ourtarget binary) Entering Damn Vulnerable ARM Router CONSOLE (/bin/sh) [+] Logging enabled [+] EMUX Debug log - /home/r0/workspace/logs/emuxdebug.log [+] QEMU Console log - qemuconsole.log [+] chroot /emux/DV-ARM/rootfs-arm /.emux/emuxshell Script started, output log file is '/home/r0/workspace/logs/emuxdebug.log'. BusyBox v1.23.2 (2021-10-14 18:26:48 IST) built-in shell (ash) / # nweb 80 /www/nweb/ 6. Manually start the nweb web server from the Busybox prompt ./emux-docker-shell [emux-docker !] ~$ curl http://192.168.100.2 <h1>Ringzer0 Hackme</h1> 7. Start another emux-docker-shell and test nweb
  • 19.
    @therealsaumil @_ringzer0 Grab the attackscripts! [emux-docker !] ~$ cd workspace [emux-docker !] ~/workspace$ wget https://saumil.net/tmp/attack1.py --2022-07-07 14:12:48-- https://saumil.net/tmp/attack1.py Resolving saumil.net (saumil.net)... 208.113.163.5 Connecting to saumil.net (saumil.net)|208.113.163.5|:443... connected. HTTP request sent, awaiting response... 200 OK Length: 535 [text/plain] Saving to: 'attack1.py' attack1.py 100%[=======================>] 535 --.-KB/s in 0s 2022-07-07 14:12:50 (58.9 MB/s) - 'attack1.py' saved [535/535] [emux-docker !] ~/workspace$ chmod +x attack1.py 8. From the emux-docker-shell grab the following attack scripts
  • 20.
  • 21.
    @therealsaumil @_ringzer0 HERE BE THEGOODS CODE: https://github.com/therealsaumil/emux !- ANNOUNCEMENTS: @therealsaumil DOCS: https://emux.exploitlab.net/
  • 22.
  • 23.