New subject: Samsung GT-I9023 Google Nexus S memory acquisition and analysis

24 Jul 2014

      Hi all,

I pre-ordered “The Art of Memory Forensics” at March 22nd :-) and as of
today delivery is estimated for September 1st :-(. I really hope there
is a chapter about debugging the memory acquisition process. ;-)

Meanwhile may I kindly ask for your advice/hints how to debug the
following? I am not able to successfully acquire and analyze a Nexus S
Android memory dump.

Where could I start to look for errors?
How can I assure that the dump is valid?
How can I assure that the profile is valid?

Any hint is highly appreciated! :-)

Thank you,
Philipp

************************************************************
0  Where I failed :-(

Google at [1] offers three “Factory Images ‘soju’ for Nexus S (worldwide
version, i9020t and i9023)”:
2.3.6 (GRK39F)
4.0.4 (IMM76D)
4.1.2 (JZO54K)

Up to now I tried the first two.

Just in case the two memory dumps as well as the two Volatility profiles
are available here:
https://mega.co.nz/#F!CEczgBqR!ksYLENHXoMCU8qzSBn79WA

************************************************************
1  Nexus S with Android 2.3.6 Gingerbread

________________________________________
1.1 Prepare the phone

1.1.0 Boot loader is unlocked:
$ adb reboot bootloader
$ fastboot oem unlock

1.1.1 Get the factory image from [2] and flash it
$ tar –zxvf soju-grk39f-factory-5ab09c98.tgz
$ cd soju-grk39f
$ adb reboot bootloader
$ ./flash-all.sh

1.1.2 Start phone
Click through the initial settings
Enable USB debugging

Get version info:
$ adb shell
$ cat /proc/version
Linux version 2.6.35.7-gf5f63ef
(android-build(a)apa28.mtv.corp.google.com) (gcc version 4.4.3 (GCC) ) #1
PREEMPT Tue Aug 2 13:57:05 PDT 2011

1.1.3 Root the phone
Get custom recovery from [5] (…because otherwise ADB sideload SuperSU
won’t work) and flash custom recovery
$ adb reboot bootloader
$ fastboot flash recovery openrecovery-twrp-2.7.1.0-crespo.img

Get SuperSU from [6]
Sideload SuperSU
$ adb reboot bootloader
Go to “Recovery” -> “Advanced” -> “ADB Sideload” -> “Swipe to start
sideload”
$ adb sideload UPDATE-SuperSU-v2.01.zip

Reboot the phone

________________________________________
1.2 Prepare LiME

1.2.1 Get the Samsung kernel source from AOSP [7]
$ mkdir -p ~/android/kernel && cd $_
$ git clone https://android.googlesource.com/kernel/samsung.git
$ cd samsung
$ git checkout f5f63ef

1.2.2 Setting Up a Build Environment with AOSP from [8]
$ mkdir -p ~/android/aosp && cd $_
$ repo init -u https://android.googlesource.com/platform/manifest -b
android-2.3.6_r0.9
$ repo sync
$ . build/envsetup.sh
$ lunch full_crespo-user

Check compiler:
$ arm-eabi-gcc --version
arm-eabi-gcc (GCC) 4.4.3

Set environment variables:
$ cd ~/android/kernel/samsung
$ export ARCH=arm
$ export SUBARCH=arm
$ export CROSS_COMPILE=arm-eabi-

1.2.3 Compile the Samsung kernel

Configure the kernel:
$ make herring_defconfig

Build the Samsung kernel:
$ make

1.2.4 Download LiME  from [9] and Cross Compile
$ mkdir -p ~/android && cd $_
$ svn checkout http://lime-forensics.googlecode.com/svn/trunk/ lime
$ cd ~/android/lime/src

Edit Makefile
(I take CCPATH from  printenv | grep arm-eabi )
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
obj-m := lime.o
lime-objs := tcp.o disk.o main.o

KDIR := ~/android/kernel/samsung
CCPATH := ~/android/aosp/prebuilt/linux-x86/toolchain/arm-eabi-4.4.3/bin
PWD := $(shell pwd)

default:
	$(MAKE) ARCH=arm CROSS_COMPILE=$(CCPATH)/arm-eabi- -C $(KDIR) M=$(PWD)
modules
	$(CCPATH)/arm-eabi-strip --strip-unneeded lime.ko

	$(MAKE) tidy

tidy:
	rm -f *.o *.mod.c Module.symvers Module.markers modules.order \.*.o.cmd
\.*.ko.cmd \.*.o.d
	rm -rf \.tmp_versions

clean:
	$(MAKE) tidy
	rm -f *.ko
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Build LiME module:
$ make

________________________________________
1.3 Dump volatile memory
$ adb push ~/android/lime/src/lime.ko /sdcard/lime.ko

Screen must be unlocked now in order to grant ADB shell root access

$ adb shell
$ su
# insmod /sdcard/lime.ko "path=/sdcard/lime.dump format=lime"
# exit
$ exit
$ adb pull /sdcard/lime.dump ~/android/dump/NexusS_2.3.6.dump

________________________________________
1.4 Build a Volatility Profile

Get Volatility from [10]:
$ svn checkout https://volatility.googlecode.com/svn/trunk/
~/android/volatility
$ cd ~/android/volatility/tools/linux

Edit Makefile:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
obj-m += module.o
KDIR := ~/android/kernel/samsung
CCPATH := ~/android/aosp/prebuilt/linux-x86/toolchain/arm-eabi-4.4.3/bin

-include version.mk

all: dwarf

dwarf: module.c
	$(MAKE) ARCH=arm CROSS_COMPILE=$(CCPATH)/arm-eabi- -C $(KDIR)
CONFIG_DEBUG_INFO=y M=$(PWD) modules
	dwarfdump -di module.ko > module.dwarf
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Build module:
$ make

Zip profile:
$ zip
~/android/volatility/volatility/plugins/overlays/linux/_NexusS_2.3.6_GRK39F_.zip
module.dwarf ~/android/kernel/samsung/System.map

________________________________________
1.5 Examine the Memory Dump with Volatility

$ cd ~/android/volatility/
$
$ python vol.py --info | grep Linux
Volatility Foundation Volatility Framework 2.3.1
Linux_NexusS_2_3_6_GRK39F_ARM - A Profile for Linux
_NexusS_2.3.6_GRK39F_ ARM
linux_banner            - Prints the Linux banner information
linux_yarascan          - A shell in the Linux memory image
$
$ python vol.py --profile=Linux_NexusS_2_3_6_GRK39F_ARM -f
~/android/dump/NexusS_2.3.6.dump linux_pslist
Volatility Foundation Volatility Framework 2.3.1
Offset     Name                 Pid             Uid             Gid
DTB        Start Time
---------- -------------------- --------------- --------------- ------
---------- ----------
No suitable address space mapping found
Tried to open image as:
MachOAddressSpace: mac: need base
LimeAddressSpace: lime: need base
WindowsHiberFileSpace32: No base Address Space
WindowsCrashDumpSpace64: No base Address Space
HPAKAddressSpace: No base Address Space
VirtualBoxCoreDumpElf64: No base Address Space
VMWareSnapshotFile: No base Address Space
WindowsCrashDumpSpace32: No base Address Space
AMD64PagedMemory: No base Address Space
IA32PagedMemoryPae: No base Address Space
IA32PagedMemory: No base Address Space
MachOAddressSpace: MachO Header signature invalid
MachOAddressSpace: MachO Header signature invalid
LimeAddressSpace: Invalid Lime header signature
WindowsHiberFileSpace32: PO_MEMORY_IMAGE is not available in profile
WindowsCrashDumpSpace64: Header signature invalid
HPAKAddressSpace: Invalid magic found
VirtualBoxCoreDumpElf64: ELF64 Header signature invalid
VMWareSnapshotFile: Invalid VMware signature: 0x1
WindowsCrashDumpSpace32: Header signature invalid
AMD64PagedMemory: Incompatible profile Linux_NexusS_2_3_6_GRK39F_ARM
selected
IA32PagedMemoryPae: Failed valid Address Space check
IA32PagedMemory: Failed valid Address Space check
FileAddressSpace: Must be first Address Space
ArmAddressSpace: Failed valid Address Space check

________________________________________
1.6 First attempt to debug

$ xxd -l 32 ~/android/dump/NexusS_2.3.6.dump
0000000: 454d 694c 0100 0000 0000 0040 0000 0000  EMiL.......@....
0000010: ffff ff4f 0000 0000 0000 0000 0000 0000  ...O............

=>
magic: 0x4c69 4d45 -> LiME
version: 0x0000 0001 -> 1
s_addr: 0x0000 0000 4000 0000
e_addr: 0x0000 0000 4fff ffff
reserved: 0x0000 0000 0000 0000

=> Address range is:
$ python -c 'print int(0x4fffffff) - int(0x40000000) + 1'
268435456

But file size is much bigger:
$ stat -c %s ~/android/dump/NexusS_2.3.6.dump
401604672

268.435.456 Bytes + 32 Bytes Header != 401.604.672 Bytes file size!!!

************************************************************
2  Nexus S with Android 4.0.4 Ice Cream Sandwich

________________________________________
2.1 Prepare the phone

2.1.0 Boot loader is unlocked

2.1.1 Get the factory image from [3] and flash it
$ tar –zxvf soju-imm76d-factory-ca4ae9ee.tgz
$ cd soju-imm76d
$ adb reboot bootloader
$ ./flash-all.sh

2.1.2 Start phone
- as described before –

$ cat /proc/version
Linux version 3.0.8-g6656123 (android-build(a)vpbs1.mtv.corp.google.com)
(gcc version 4.4.3 (GCC) ) #1 PREEMPT Thu Feb 2 16:56:02 PST 2012

2.1.3 Root the phone
- as described before -

________________________________________
2.2 Prepare LiME

2.2.1 Get the Samsung kernel source from AOSP [7]
$ mkdir -p ~/android/kernel && cd $_
$ git clone https://android.googlesource.com/kernel/samsung.git
$ cd samsung
$ git checkout 6656123

2.2.2 Setting Up a Build Environment with AOSP from [8]
$ mkdir -p ~/android/aosp && cd $_
$ repo init -u https://android.googlesource.com/platform/manifest -b
android-4.0.4_r1.1
$ repo sync
$ . build/envsetup.sh
$ lunch full_crespo-user

Check compiler:
$ arm-eabi-gcc --version
arm-eabi-gcc (GCC) 4.4.3

Set environment variables:
$ cd ~/android/kernel/samsung
$ export ARCH=arm
$ export SUBARCH=arm
$ export CROSS_COMPILE=arm-eabi-

2.2.3 Compile the Samsung kernel
- as described before -

2.2.4 Download LiME  from [9] and Cross Compile
- as described before -

________________________________________
2.3 Dump volatile memory
- as described before –

$ adb pull /sdcard/lime.dump ~/android/dump/NexusS_4.0.4.dump

________________________________________
2.4 Build a Volatility Profile

Get and build Volatility - as described before -

$ zip
~/android/volatility/volatility/plugins/overlays/linux/_NexusS_4.0.4_IMM76D_.zip
module.dwarf ~/android/kernel/samsung/System.map

________________________________________
2.5 Examine the Memory Dump with Volatility

$ cd ~/android/volatility/
$
$ python vol.py --info | grep Linux
Volatility Foundation Volatility Framework 2.3.1
linux_banner            - Prints the Linux banner information
linux_yarascan          - A shell in the Linux memory image
Linux_NexusS_2_3_6_GRK39F_ARM - A Profile for Linux
_NexusS_2.3.6_GRK39F_ ARM
Linux_NexusS_4_0_4_IMM76D_ARM - A Profile for Linux
_NexusS_4.0.4_IMM76D_ ARM
$
$ python vol.py --profile=Linux_NexusS_4_0_4_IMM76D_ARM -f
~/android/dump/NexusS_4.0.4.dump linux_pslist
Volatility Foundation Volatility Framework 2.3.1
Offset     Name                 Pid             Uid             Gid
DTB        Start Time
---------- -------------------- --------------- --------------- ------
---------- ----------
No suitable address space mapping found
Tried to open image as:
- the rest as described before –

________________________________________
2.6 First attempt to debug

$ xxd -l 32 ~/android/dump/NexusS_2.3.6.dump
0000000: 454d 694c 0100 0000 0000 0040 0000 0000  EMiL.......@....
0000010: ffff ff4f 0000 0000 0000 0000 0000 0000  ...O............

=>
magic: 0x4c69 4d45 -> LiME
version: 0x0000 0001 -> 1
s_addr: 0x0000 0000 4000 0000
e_addr: 0x0000 0000 4fff ffff
reserved: 0x0000 0000 0000 0000

=> Address range is:
$ python -c 'print int(0x4fffffff) - int(0x40000000) + 1'
268435456

But file size is still bigger:
$ stat -c %s ~/android/dump/NexusS_4.0.4.dump
325775424

268.435.456 Bytes + 32 Bytes Header != 325.775.424 Bytes file size!!!

************************************************************
3  Links

[1] https://developers.google.com/android/nexus/images\#soju
[2] https://dl.google.com/dl/android/aosp/soju-grk39f-factory-5ab09c98.tgz
[3] https://dl.google.com/dl/android/aosp/soju-imm76d-factory-ca4ae9ee.tgz
[4] https://dl.google.com/dl/android/aosp/soju-jzo54k-factory-36602333.tgz
[5]
http://techerrata.com/file/twrp2/crespo/openrecovery-twrp-2.7.1.0-crespo.img
[6] http://download.chainfire.eu/supersu
[7] https://android.googlesource.com/kernel/samsung.git
[8] https://android.googlesource.com/platform/manifest
[9] http://lime-forensics.googlecode.com/svn/trunk/
[10] https://volatility.googlecode.com/svn/trunk/