exploring Dahua firmware

A sidetrack from these two posts: Extracting password from Dahua firmware image and Dahua IPC-HFW4300S

To recap: I managed to extract various UBI (NAND flash) images from firmware image.

binwalk -e {firmware_file}

Which gave me the following files:


I started with romfs-x.ubifs.img as initial grep revealed it contained root password hash (matched to ‘vizxv’).

Mounting UBIFS is not a straight forward (eg cannot use loop).
With help of two guides I found (here and here) I managed to figure out how to mount these images.

apt-get install mtd-utils
modprobe nandsim first_id_byte=0x20 second_id_byte=0xaa third_id_byte=0x00 fourth_id_byte=0x15
modprobe ubi mtd=0
tail -c+65 romfs-x.ubifs.img > romfs
ubiformat /dev/mtd0 -f romfs
ubiattach -p /dev/mtd0
mkdir target
mount -t ubifs /dev/ubi0_0 target

note: tail -c65 strips the header.

mounting contents of romfs-x.ubifs.img gives some insight on the root file structure:

drwxr-xr-x  2  500  500 5192 Apr  2  2013 bin
drwxr-xr-x  7  500  500  480 Feb 18  2012 dev
drwxr-xr-x  6  500  500  960 Feb 24  2013 etc
drwxr-xr-x  2  500  500  160 Jan 13  2012 home
drwxr-xr-x  2  500  500 4832 Feb 22  2013 lib
lrwxrwxrwx  1  500  500   11 Dec 31  2013 linuxrc -> bin/busybox
drwxr-xr-x 13  500  500  864 Dec  5  2012 mnt
drwxr-xr-x  2  500  500  160 Jan 13  2012 nfs
drwxr-xr-x  2  500  500  160 Jan 13  2012 proc
drwxr-xr-x  2  500  500  160 Jan 13  2012 root
drwxr-xr-x  2  500  500 2728 Dec 25  2013 sbin
drwxr-xr-x  2  500  500  160 Jan 13  2012 share
drwxr-xr-x  2  500  500  160 Jan 13  2012 slave
drwxr-xr-x  2  500  500  160 Jan 13  2012 sys
lrwxrwxrwx  1  500  500    8 Dec 31  2013 tmp -> var/tmp/
drwxr-xr-x  2  500  500  160 Jan 13  2012 usr
drwxr-xr-x  3  500  500  224 Jan 13  2012 var

looking at /etc/inittab:


the /etc/init.d/dnode sets up some of the device nodes, nothing interesting there…
while /etc/init.d/rcS contains some interesting stuff:

/sbin/ubimkvol /dev/ubi6 -s 2500000 -N config
mount -t ubifs ubi6_0 /mnt/mtd

Here what I found out from contents of each UBIFS file:

UBIFS description
check.img contains some hardware IDs
custom-x.ubifs.img /mnt/custom customisation files?
dhboot.bin.img bootloader
kernel.img kernel image
partition-x.cramfs.img contains partition.txt
pd-x.ubifs.img /mnt/pd/ product description files
romfs-x.ubifs.img / root
user-x.ubifs.img /usr/
web-x.ubifs.im /mnt/web/ webUI related files

Interesting bit regarding partition-x.cramfs.img, that it contains partition.txt:

#       name                cs         offset              size         mask_flags
  U-Boot,             0, 0x0000000000200000,    0x0000000000100000, RW
  hwid,               0, 0x0000000000300000,    0x0000000000100000, RW
  updateflag,         0, 0x0000000000400000,    0x0000000000100000, RW
  partition,          0, 0x0000000000500000,    0x0000000000100000, RW
  custom,             0, 0x0000000000600000,    0x0000000000340000, RW
  product,            0, 0x0000000000940000,    0x0000000000340000, RW
  Kernel,             0, 0x0000000000c80000,    0x0000000000580000, RW
  romfs,              0, 0x0000000001200000,    0x0000000000800000, RW
  web,                0, 0x0000000001a00000,    0x0000000000800000, RW
  user,               0, 0x0000000002200000,    0x0000000001980000, RW
  syslog,             0, 0x0000000007200000,    0x0000000000400000, RW
  config,             0, 0x0000000007600000,    0x0000000000400000, RW
  backup,             0, 0x0000000007a00000,    0x0000000000400000, RW

all this is effort was to find the telnet password...
I am missing /mnt/mtd mount point, specifically /mnt/mtd/Config/passwd file, which looks like contains telnet password (possibly?)...

UPDATE: solution to the password debacle is here (at the end of the article).

Now the question where the portion of the telnet password 7ujMko0 comes from? "Inspecting" (running strings) telnetd binary from flash image reveals that it is hard coded into telnetd. If Dahua ever changes that value I know where to find it now.

Extracting password from Dahua firmware image

I wanted to access my Dahua IPC-HFW4300S via telnet (as there is no ssh access).
Unfortunately Dahua does not provide the root password (purposely, as it is hardcoded backdoor).
The currently documented password (vizxv) does not work.

So I got the firmware image (which is achievement, considering Dahua stance on firmware) and managed to extract hash.

First of all the firmware image needs to be extracted from zip, I’ll skip this part and jump straight into extracting binary parts from the firmware:

binwalk -e {Firware_File}

The binwalk utility should have extracted the following files:


the file of interest is romfs-x.ubifs.img as it has hits when grep-ed for ‘root’:


Now we have a hash which we can brute force with John The Ripper tool.

I settled for 1.8.0 jumbo version with CUDA support.
CUDA seems to be about 2.5 times faster on Nivida GTX560ti than a very beefy 2x Intel Xeon E5-2660 (with 20 cores total).

Particular thing to I had to do to compile (beyond wget-ing and un-tar-ing the arhive) is to modify the entry from gcc-4.6 to gcc-4.8 in Makefile, as it would throw compilation error (gcc-4.6: error trying to exec ‘cc1plus’: execvp: No such file or directory).

line 152:

CCBIN = /usr/bin/gcc-4.8

‘make’ once done that (and libssl-dev is installed), and it should compile.

to run:

./john --format=md5crypt-cuda {hash_file}

The password turns out to be ‘vizxv’ (without quotes). This is not the telnet password (possibly console password).

I was directed towards correct password here: http://www.cctvforum.com/viewtopic.php?f=19&t=44381

Here are telnet credentials
username: admin
password: 7ujMko0{webui_admin_password}

For example webUI admin password is 123456 then the telnet password is 7ujMko0123456