ADB Tools 2 description

Tools for hacking ADB Epicentro routers, especially the D-Link DVA-5592 distributed by Wind in Italy to his FTTC and Fiber subscribers.

These tools are:

python3 scripts to decrypt and modify the router configuration file to recover VOIP and other passwords in plain text and to enable hidden or disabled functions. These scripts are available in python source and in .exe compiled version for Windows. The .exe files don't require Python and related additional modules
hack-script.sh used to automate the procedure to become root on the DVA-5592 router and to temporary enable (until next reboot) the upgrade with an unsigned firmware
mod-kit a folder with a firmware modification kit for the DVA-5592 router. The kit includes a couple of bash scripts and support files to enable the modification of the root file system and the generation of an unsigned firmware file to be loaded into the router thanks to the above script

Python3 scripts are based on adbtools forked from Gabriel Huber's repository (https://github.com/Yepoleb/adbtools) and use some GUI elements by Benjamin Bertrand (https://github.com/beenje/tkinter-logging-text-widget)

Decrypt and modify the router configuration file

The following Python3 scripts allows to decrypt and/or modify and encrypt the binary router configuration, locally saved using the web interface.

This allows to show hidden passwords, including the VOIP password, stored in the encrypted configuration file and to modify the configuration file to enable hidden or disabled functionalities.

Python dependencies can be installed using

pip3 install -r requirements.txt

confedit

It is the main, GUI based, tool that allows:

decryption of the router configuration
extraction of the main XML configuration file and the CPE configuration file
encryption of main XML configuration file and the XML CPE configuration file
extraction of passwords embedded in the configuration files, including the VoIP username and password
editing of various features including:
- enable restricted web GUI elements
- enable restricted CLI commands
- enable firmware upgrade/downgrade
- fix wrong ddns server: dlinkdns.con -> dlinkddns.com

confbin2xml

It is an improved version of the pkcrypt tool (see below) used for decrypting the config backup file saved from the router webinterface.

The config backup file is a binary encrypted xml file with a trailing segment of base64 encrypted CPE DATA as in the following snippet:

  <!-- CPE Data: DVA-5592/DVA-5592 system type    : 963138_VD5920 -->
  <!-- DATA
  9V/jO+TpbscUypF/41d3Ej15nwHuUp+c4wBWV4uFWb1Zb/nS6QuDiLUoZeJ2s0mksjXrARR2
  6+4XkU8c2Dt+0svzS01nAOYY6hEhWkiQhUUROsUg69qK88UvBHAiDXW0koIkZ2aOva4bci+U
  ....
  24g6a+nGht0O4xs99XXewI5uq0i/7+sf1Ic7CkscNfrS7k0n07MFPLWSV97kkmU1/+GfGwrd
  e1ICfokPdjY=
  -->

The confbin2xml.py tool extract and decrypt both files, they have similar, but not identical, content. I suppose that the two contents have to be consistent.

Python Usage example:

python3 confbin2xml.py [-l it|en] download.pem upload.pem config_full_DVA-5592_2018-06-04T222624.bin conf.xml confcpe.xml

Windows Usage example:

d:\adbtools2> confbin2xml.exe [-l it|en] download.pem upload.pem config_full_DVA-5592_2018-06-04T222624.bin conf.xml confcpe.xml

where:

-l it|en       input, optional, select language it=Italian en=English
download.pem   input, decrypting key for the main configuration file, from the firmware file system
upload.pem     input, decrypting key for the CPE Data configuration file, form the firmware file system
config_full... input, configuration file downloaded from the router web interface
conf.xml       output, main configuration file decrypted
confcpe.xml    output, CPE Data configuration file decrypted

The output files written by the tool (conf.xml and confcpe.xml) are text file in "unix format" (Line Feed as line separator) so notepad has difficulties in displaying them correctly, you can use another editor or convert them to "dos format" with a command similar to the following:

d:\adbtools2> type conf.xml | more /P > conf2.xml

in this way conf2.xml can be correctly viewed with notepad.

One interesting piece of information is the SIP username and password in plain text in both configuration file as in the following conf.xml snippet:

      <SIP>
            <AuthPassword>1234XABC</AuthPassword>
            <AuthUserName>39099123456</AuthUserName>
      </SIP>

confxml2bin

Does the opposite of confbin2xml, takes, as input, the main XML configuration file, the CPE XML configuration file, the two encrypting keys and generates the encrypted binary XML file ready to be loaded into the router.

Using confbin2xml and confxml2bin it is possible to extract the two XML files, modify them and generate the new encrypted binary XML file, ready to be loaded into the router.

Python usage example:

python3 confxml2bin.py [-l it|en] download.pem upload.pem conf.xml confcpe.xml conf.bin

Windows usage example:

d:\adbtools2> confxml2bin.exe [-l it|en] download.pem upload.pem conf.xml confcpe.xml conf.bin

where: -l it|en input, optional, select language it=Italian en=English download.pem input, encrypting key for the main configuration file, from the firmware file system upload.pem input, encrypting key for the CPE Data configuration file, form the firmware file system conf.xml input, main configuration file confcpe.xml input, CPE Data configuration file conf.bin output, configuration file ready to be uploaded to the router web interface

pkcrypt

Tool used for encrypting/decrypting the config backups from the webinterface. Uses an RSA public key for AES encryption. Only works with configs created with version E_3.4.0 or later (May 2017) as older ones tried to use asymmetric encryption without a private key, which makes the configs impossible to decrypt, even for the devices themselves. Key can be found at /etc/certs/download.pem in the firmware image.

Python usage example:

python3 pkcrypt.py [-l it|en] sym_decrypt download.pem config.bin config.xml

Windows usage example:

d:\adbtools2> pkcrypt.exe [-l it|en] sym_decrypt download.pem config.bin config.xml

How to become root on the D-Link DVA-5592 router

Previous known Epicentro vulnerabilities (like https://www.exploit-db.com/exploits/44983/) has been closed in the software version (_ADB_PlatformSoftwareVersion=6.0.0.0028) used by this router, so it was necessary to to search another unexploited vulnerability.

The procedure described here has been tested on the DVA-5592 router, probably it will function on other Epicentro routers, eventually with some modifications.

Get an unprivileged busybox command prompt

A telnet into this router gives a /bin/clish command prompt. Clish (or Klish) si an open source project (http://libcode.org/projects/klish/) to give a "Cisco like" interface. This shell is configured through an xml configuration file.

Looking at the startup scripts (see below about router file system analysis) and at the /bin/clish script it is possible to see that the normal configuration file is /tmp/clish/startup.xml (/tmp/clish links to /etc/clish in "normal" mode and to /etc/clish/prod in "factory mode"), in this file there is an "hidden" command that isn't auto-completed and doesn't show in the clish CLI:

   <COMMAND name="factory-mode" help="hidden">
      <ACTION>
	   cmclient DUMPDM FactoryData /tmp/cfg/FactoryData.xml > /dev/null
	   nvramUpdate Feature 0x2 > /dev/null
	   cmclient REBOOT > /dev/null
      </ACTION>
   </COMMAND>

So it is possible to enter "factory-mode" with the following commands:

valerio@ubuntu-hp:~$ telnet 192.168.1.1
Trying 192.168.1.1...
Connected to 192.168.1.1.
Escape character is '^]'.
Login: admin
Password:

********************************************
*                 D-Link                   *
*                                          *
*      WARNING: Authorised Access Only     *
********************************************

Welcome
DLINK# factory
DLINK(factory)# factory-mode
DLINK(factory)#
DLINK(factory)# Connection closed by foreign host.
valerio@ubuntu-hp:~$

The system reboots and enters factory mode. The configuration is wiped out and the router doesn't operate normally: DHCP server is not working, WiFi has some esoteric, but unusable, SSIDs and Internet connection doesn't work. It is needed to configure a static IP address on the PC to communicate with the router's default IP (192.168.1.1).

But in this mode it is possible to enter an unprivileged busybox shell:

valerio@ubuntu-hp:~$ telnet 192.168.1.1
Trying 192.168.1.1...
Connected to 192.168.1.1.
Escape character is '^]'.
Login: admin
Password:

********************************************
*                 D-Link                   *
*                                          *
*      WARNING: Authorised Access Only     *
********************************************

Welcome
DLINK# system shell


BusyBox v1.17.3 (2018-04-11 12:29:54 CEST) built-in shell (ash)
Enter 'help' for a list of built-in commands.

/root $

The role of the cm daemon running with root privileges

The result of file system analysis shows that large part of the router configuration modification, in response to user's CLI commands or web interaction, is done by a system process, /sbin/cm, running with root privileges:

/root $ ps -ef | egrep 'PID| cm'
PID USER       VSZ STAT COMMAND
356 0         2560 S    cm

This process (cm probably means "Configuration Manager") is started by /etc/init.d/services.sh startup script, it is a daemon listening for commands on the socket file /tmp/cmctl.

Commands are given using the cmclient configuration command, it is not a program but it is interpreted directly by busybox probably through a compiled plugin. cmclient simply writes commands to /tmp/cmctl.

Also clish has a plugin to talk directly to cm through the /tmp/cmctl socket file.

During the router boot cmclient is used by startup files to configure the /sbin/cm process giving it location of xml configuration files.

During normal operations cmclient is executed by the web interface or the clish CLI in response to user's request to get configuration information or to change configuration parameters; in these cases cmclient is executed by an unprivileged user (the web interface runs as user nobody, the CLI runs, usually, as user admin).

The daemon cm, to change router configuration, uses "helper scripts" located in the /etc/ah folder; so, for example, to add a new user or to change current user's password it executes the helper script /etc/ah/Users.sh passing it the correct parameters.

The cm process knows that it has to call /etc/ah/Users.sh through:

a startup script that executes the command:

  cmclient DOM Device /etc/cm/tr181/dom/

the cm daemon process every file in the above folder, including /etc/cm/tr181/dom/Management.xml
in the above file there is the following xml snippet:

    <object name="Users.User.{i}."
          access="readOnly"
          minEntries="0"
          maxEntries="unbounded"
          numEntriesParameter="UserNumberOfEntries"
          enableParameter="Enable"
          set="Users.sh"
          add="Users.sh"
          del="Users.sh"
    >

the cm daemon prepend the /etc/ah/ path in front of Users.sh

Exploiting the cm daemon to run a script with root privileges

The interesting thing is that it is possible to re-configure the cm daemon giving it, through cmclient, a command to load a new XML file located, for example, in the /tmp folder. Each definition in a new XML file overwrites existing definitions, This means that it is possible to:

copy /etc/cm/tr181/dom/Management.xml into /tmp
modify /tmp/Managemente.xml to load ../../tmp/Users.sh (/tmp/Users.sh) instead of Users.sh (/etc/ah/Users.sh)
give the command to reconfigure the cm daemon: cmclient DOM Device /tmp/Management.xml
copy /etc/ah/Users.sh into /tmp
modify /tmp/Users.sh to modify /tmp/passwd (/etc/passwd links to this file) to remove the '*' from the root password field to allow su - root without password
have cm execute the modified /tmp/Users.sh script with root privileges with the command: cmclient ADD Device.Users.User

hack-script.sh

This is a script to be executed on the /bin/ash command line interface in the router to exploit the above vulnerability and become root.

This script does exactly the above steps, so to become root, in an unprivileged busybox command prompt, it is needed to:

/root $ cat > /tmp/hack-script.sh
   do a copy and paste of the script
   press CTRL-D to terminate the copy

/root $ chmod a+x /tmp/hack-script.sh
/root $ /tmp/hack-script.sh

 ....

/root $ su -


BusyBox v1.17.3 (2018-04-11 12:29:54 CEST) built-in shell (ash)
Enter 'help' for a list of built-in commands.

      ___           ___           ___           ___     
     |\__\         /\  \         /\  \         /\  \    
     |:|  |       /::\  \       /::\  \       /::\  \   
     |:|  |      /:/\:\  \     /:/\:\  \     /:/\:\  \  
     |:|__|__   /::\~\:\  \   /::\~\:\  \   _\:\~\:\  \
     /::::\__\ /:/\:\ \:\__\ /:/\:\ \:\__\ /\ \:\ \:\__\
    /:/~~/~    \/__\:\/:/  / \/__\:\/:/  / \:\ \:\ \/__/
   /:/  /           \::/  /       \::/  /   \:\ \:\__\  
   \/__/            /:/  /         \/__/     \:\/:/  /  
                   /:/  /                     \::/  /   
                   \/__/                       \/__/    r41358.07b1b3a7  
..................................................................
 yet another purposeful solution by  Advanced Digital Broadcast SA
..................................................................
root@localhost:~# id
uid=0(root) gid=0(root) groups=0(root),19(remoteaccess),20(localaccess)
root@localhost:~#

As root, it is now possible to modify everything, but I have found that modifying the root jffs2 file system I start getting, on the console, error messages related to jffs2 checksum errors. The root jffs2 file system is mounted read/write, but the router firmware never modify it, and treat it as if it was mounted read only. Only the firmware upgrade procedure rewrites the root jffs2 file system.

I don't know why this happens, it seems (but not fully sure) that adding files doesn't give checksum error messages, but modifying existing files does.

The hack-script.sh has another feature: the possibility to temporary upgrade the router with an unsigned firmware file. To do so it

copy the /usr/sbin/upgrade.sh in /tmp/upgrade.sh and replace the following snippet

sig_verify $file 2> /dev/null
ret_code=$?

with

sig_verify $file 2> /dev/null
ret_code=0

sig_verify is the executable used to check that the firmware file has been digitally signed with the supplier's private key. The public key is embedded in this executable file. This modification means that an unsigned firmware will be treated as a signed one.

execute the mount --bind command to temporary "replace" /usr/sbin/upgrade.sh and temporary (until reboot) allow an upgrade with an unsigned firmware:

su -c "mount --bind /tmp/upgrade.sh /usr/sbin/upgrade.sh" -

after the execution of hack-script.sh, before reboot and still in "factory mode" it is possible to upgrade, via web interface, the router with an unsigned firmware generated with the "Firmware Modification Kit" described below.

To return to normal mode of operation it is needed to exit factory mode with the following command in the clish shell

DLINK# restore default-setting

The router will return to the normal mode, but the previous configuration has been wiped out, so the router restarts as if it was resetted to factory configuration.

Firmware modification kit

This kit, located in the folder mod-kit in this repository, allows to extract the root file system from an official firmware file, modify and/or add new files to this root file system and generate a new, unsigned, firmware file, ready to be uploaded to the router, via web interface, following the procedure described above and involving the use of hack-script.sh.

Current implementation has the following limitations (some of them may be removed in future releases):

only the DVA-5592_A1_WI_20180405.sig firmware can be modified (firmware for the device D-Link DVA-5592 distributed in Italy by Wind and released on 2018/04/05)
new root file system image, incorporating custom modifications, must not be greater than current root file system image size
runs only on Linux (this limitation will not be removed in future releases)

Firmware modification kit prerequisites

The kit requires some software to be available, the two most important required software are:

Jefferson available at https://github.com/sviehb/jefferson, to extract the jffs2 root file system from the JFFS2 image file
mkfs.jffs2, part of mtd-utils (http://www.linux-mtd.infradead.org/source.html), with the lzma patch to support lzma compression. The version of mkfs.jffs2, usually available on package repositories, doesn't include the lzma patch. I grabbed the lzma patch from the openwrt project and included it in this repository.

To get mkfs.jffs2 with lzma support there are at least two options: get a compiled version with the lzma patch included from an OpenWRT SDK or compile the mtd-utils from source.

To compile the mtd-utils, some additional packages can be needed on the Linux system used for compilation, for example, in my case, on my Ubuntu 16.04.05, I had to install:

sudo apt install liblzo2-2 liblzo2-dev libacl1 libacl1-dev

If some errors pop-up during compilation it is always possible to google the error and find what package is needed to install to resolve the issue.

To compile mtd-utils and apply the lzma patch included in this repository I did:

    # get the mtd-utils version v2.0.2 (last stable version, currently)
    git clone -b v2.0.2 --single-branch --depth 1 git://git.infradead.org/mtd-utils.git

    # apply the lzma patch included in this repository
    cd mtd-utils/
    patch -p1  < /path/to/this/repository/mod-kit/mtd-utils-lzma_jffs2.patch

    # build the mtd-utils packages
    ./autogen.sh
    ./configure
    make

    # check that lzma compression is included
    ./mkfs.jffs2 -L
    mkfs.jffs2: error!:
          zlib priority:80 enabled
          lzma priority:70 enabled
         rtime priority:50 enabled

    # copy the mkfs.jffs2 command in a suitable location, for example
    sudo cp mkfs.jffs2 /usr/local/bin/mkfs.jffs2-lzma

Content of the firmware modification kit folder (mod-kit)

The folder mod-kit contains the following files/directories:

mod-kit-configure.sh this script prepare and create the directory tree (mod-kit-dir) that will contain the original firmware file, the original extracted root file system, the patch directory, the overlay directory, the new modified root file system, the new modified and unsigned firmware file. This is the first script to run.
mod-kit-run.sh this is the main script that extracts the root file system from the original firmware, apply patches to it, apply overlay files, remove files listed in root-rm-files.txt, executes the pre-image-script.sh and generate the new unsigned firmware file.
device-table.txt the device table used by mkfs.jffs2 to allow creation of /dev/console and /dev/null in the jffs2 root file system image. This is needed because the normal user (not root), that runs this kit, has no rights to create a special device file. This file is copied to the mod-kit-dir and can be customized, if needed.
root-permissions.acl this file contains the correct file owner and mode of each file in the root file system. This file is needed because files extracted by Jefferson haven't the correct file mode and ownership. This file is copied to the mod-kit-dir and can be customized, if needed.
mtd-utils-lzma_jffs2.patch this is the patch to apply to mtd-utils to add support for lzma compression (see above)
root-patch this is a directory with same folder structure as the root file system and a corresponding file for each file that needs to be patched on the original root file system. The patch file name is the same as the file to be patched with the suffix .patch. This directory is copied to the mod-kit-dir and can be customized, if needed. Currently only the following files will be patched:
- /etc/passwd.orig to replace the :*: from the root entry, with a valid encrypted password field, the default password is no.wordpass, but can be changed passing a parameter to mod-kit-run.sh; this allows su - to root. Please note that root cannot login with telnet or ssh, and no login is allowed from Internet.
- /usr/sbin/upgrade.sh to allow firmware upgrade with unsigned firmware file, using the web interface.
- /usr/sbin/usb_hotplug_sw_upgrade.sh to allow firmware upgrade with unsigned firmware file, using a USB key.
- /etc/clish/startup.xml to allow the command "system shell" in normal mode (currently this command is available only in factory mode). This command allows to escape the clish interface and use a standard /bin/ash (busybox) CLI.
root-overlay this is a directory with same folder structure as the root file system, files present in this directory will be written to the new root file system, after the above patches have been applied. This directory is copied to the mod-kit-dir and can be customized. Currently the main folder and files located in this directory are the followings:
- /opt directory, it is the mount point for an ext2, ext3 or ext4 first partition on a USB key where to install entware (https://github.com/Entware)
- /etc/init.d/entware.sh and related link files in /etc/rc.d (K00entware.sh and S99entware.sh). This script is executed on boot, with parameter "boot", and on shutdown, with parameter "shutdwon", and initializes or terminates the entware environment. It can be manually executed, with parameter "install" to install the entware environment on an available ext2, ext3 or ext4 first partition on an attached USB key (see below for instructions)
- /usr/bin/wget it is needed for initial entware installation
- /usr/lib/libtirpc.so.3.0.0 and related links, they are needed by wget
root-rm-files.txt this file lists, one per line, files and/or directories to be removed from the new root file system. '#' as first char in a line is a comment and it is ignored, a trailing '/' indicate a directory. This file is copied to the mod-kit-dir and can be customized.
pre-image-script.sh this script will be executed just before the creation of the new root file system image and can be used to further sutomize the new root file system. By default it modifies the file /etc/banner to add a line identifying adbtools2 version and firmware build date. It is copied to the mod-kit-dir and can be customized.

Script mod-kit-configure.sh

This script creates the directory tree where the firmware modification kit will store original firmware file, original root file system, modified root file system, modified and unsigned firmware file system and other support files.

Script usage is the following:

usage: ./mod-kit-configure.sh [ -d basedir ] [ -j /path/to/mkfs.jffs2 ] <firmware file>
   -d basedir (defautl $HOME/mod-kit)
   -j /path/to/mkfs.jffs2 (default /usr/local/bin/mkfs.jffs2-lzma)
   -h this help

   example:
   ./mod-kit-configure.sh /path/to/DVA-5592_A1_WI_20180405.sig

This script will create the following directories, and partially populate then, under the basedir provided with the -d option (default is $HOME/mod-kit)

input the original firmware file is copied to this directory, the original root file system images and other original intermediate images are stored on this directory
input/root the original root file system, extracted with Jefferson by the mod-kit-run.sh script is stored there
output the modified firmware file is generated, by mod-kit-run.sh, in this directory, intermediate modified file system images are stored in this directory
output/root the modified root file system is stored in this directory. The original file system in input/root is copied here, then patches from root-patch directories are applied, then files in the root-overlay directory are copied here.
root-patch this is a directory with same folder structure as the root file system and a corresponding file for each file that needs to be patched on the original root file system. The patch file name is the same as the file to be patched with the suffix .patch. This directory is initially populated by the mod-kit-configure.sh script from the similar directory in this repository. The user can customize this directory adding more patch files.
root-overlay this is a directory with same folder structure as the root file system, files present on this directory will be written to the new root file system, after the above patches have been applied by the mod-kit-run.sh script. This directory is initially populated by the mod-kit-configure.sh script from the similar directory in this repository. The user can customize this directory adding more files and or directories.
device-table.txt the device table used by mkfs.jffs2 to allow creation of /dev/console and /dev/null in the jffs2 root file system image. This is needed because the normal user (not root), that runs this kit, has no rights to create a special device file. This file is populated by the mod-kit-configure.sh script from the similar file in this repository.
root-permissions.acl this file contains the correct file owner and mode of each file in the root file system. This file is needed because files extracted by Jefferson haven't the correct file mode and ownership. This file is populated by the mod-kit-configure.sh script from the similar file in this repository.
root-rm-files.txt this file lists, one per line, files and/or directories to be removed from the new root file system. '#' as first char in a line is a comment and it is ignored, a trailing '/' indicate a directory. This file can be customized.
pre-image-script.sh this script will be executed just before the creation of the new root file system image and can be used to further customize the new root file system. By default it modifies the file /etc/banner to add a line identifying adbtools2 version and firmware build date and can be customized.

Script mod-kit-run.sh

This script does the main job to generate the modified unsigned firmware file:

extract the root file system image from the original firmware file
extract the original file system from the image into input/root
copy input/root to output/root
apply patches from root-patches to output/root
copy additional files/directory from root-overlay to output/root
generate the new root file system image
insert the new root file system image into the new unsigned firmware files
if xdelta3 is available, generate and xdelta file to binary patch the original firmware to obtain the new modified firmware file.

Usage of this script is the following:

usage: ./mod-kit-run.sh [ -c ] [ -h ] [-p password]
       -c             clean all generated files from a previous run
       -p password    set password for root, default 'no.wordpass'
       -h             print this help

Entware installation

Entware (https://github.com/Entware/Entware) is a software repository for embedded devices with more than 2000 packages and a package manager (opkg) to easily install them and to automatically resolve dependencies.

Entware packages are installed under the /opt directory tree (in this case this is the first ext2, ext3 or ext4 partition of an attached USB key) and use libraries, configurations files etc. inside the /opt tree; this means that entware remains in some way separated from the firmware installed on the device and does not interfere much with the installed firmware.

To remove entware it is enough to unmount the /opt directory or to remove everything from the USB key partition mounted on /opt.

To install entware, on a router running the modified firmware, it is needed to:

attach an already formatted USB key with the first, or only, partition formatted with an ext2, ext3 or ext4 file system. Ext4 is preferred.
telnet to the router and executes the command /etc/init.d/entware.sh; usage of this command for installation is:
```
/etc/init.d/entware.sh install [generic | alternative]
   generic:      do a standard installation (/opt/etc/passwd is a link to
                 system wide /etc/passwd)
   alternative:  do an alternative installation (/opt/etc/passwd is a file
                 with no relation to the system wide /etc/passwd)
```
The difference between "standard" and "alternative" installation is explained in the entware web site. "Alternative" is recommended, and is the default, because if some software creates additional users during installation, it would get lost after reboot with a "standard" installation because the router keeps the system wide password in /tmp/passwd and this file is recreated at boot based on router configuration saved in XML files.
entware executables are installed in /opt/bin and /opt/sbin so, to be able to easily execute them, it is recommended to add these two directories to the PATH, it can be achieved sourcing /opt/etc/profile with
```
root@dlinkrouter:~# . /opt/etc/profile
```
please note that sourcing /opt/etc/profile puts /opt/bin and /opt/sbin as the first two directories of the PATH, so entware commands with same name as the firmware commands will take precedence. Sometimes it is not what expected.

A successful entware installation is shown below:

valerio@ubuntu-hp:~/temp/entware$ telnet 192.168.1.1
Trying 192.168.1.1...
Connected to 192.168.1.1.
Escape character is '^]'.
Login: admin
Password:

********************************************
*                 D-Link                   *
*                                          *
*      WARNING: Authorised Access Only     *
********************************************

Welcome
DLINK# system shell


BusyBox v1.17.3 (2018-04-11 12:29:54 CEST) built-in shell (ash)
Enter 'help' for a list of built-in commands.

/root $ su -


BusyBox v1.17.3 (2018-04-11 12:29:54 CEST) built-in shell (ash)
Enter 'help' for a list of built-in commands.

      ___           ___           ___           ___     
     |\__\         /\  \         /\  \         /\  \    
     |:|  |       /::\  \       /::\  \       /::\  \   
     |:|  |      /:/\:\  \     /:/\:\  \     /:/\:\  \  
     |:|__|__   /::\~\:\  \   /::\~\:\  \   _\:\~\:\  \
     /::::\__\ /:/\:\ \:\__\ /:/\:\ \:\__\ /\ \:\ \:\__\
    /:/~~/~    \/__\:\/:/  / \/__\:\/:/  / \:\ \:\ \/__/
   /:/  /           \::/  /       \::/  /   \:\ \:\__\  
   \/__/            /:/  /         \/__/     \:\/:/  /  
                   /:/  /                     \::/  /   
                   \/__/                       \/__/    r41358.07b1b3a7  
..................................................................
 yet another purposeful solution by  Advanced Digital Broadcast SA
..................................................................
root@dlinkrouter:~# /etc/init.d/entware.sh install alternative
entware.sh: fstype: ext3
entware.sh: module ext2 already loaded
entware.sh: module mbcache already loaded
entware.sh: module jbd already loaded
entware.sh: module jbd2 already loaded
entware.sh: module ext3 already loaded
entware.sh: module ext4 already loaded
entware.sh: /opt/etc/init.d/rc.unslung not found
entware.sh: entware software not found on /opt
entware.sh: Entware Installation
entware.sh: downloading http://bin.entware.net/armv7sf-k3.2/installer/alternative.sh
Connecting to bin.entware.net (81.4.123.217:80)
alternative.sh       100% |***************************************************************************************************************************|  2031   0:00:00 ETA
entware.sh: installing entware, executing /tmp/alternative.sh
Info: Checking for prerequisites and creating folders...
Warning: Folder /opt exists!
Info: Opkg package manager deployment...
Connecting to bin.entware.net (81.4.123.217:80)
opkg                 100% |***************************************************************************************************************************|   131k  0:00:00 ETA
Connecting to bin.entware.net (81.4.123.217:80)
opkg.conf            100% |***************************************************************************************************************************|   190   0:00:00 ETA
Connecting to bin.entware.net (81.4.123.217:80)
ld-2.27.so           100% |***************************************************************************************************************************|   135k  0:00:00 ETA
Connecting to bin.entware.net (81.4.123.217:80)
libc-2.27.so         100% |***************************************************************************************************************************|  1218k  0:00:00 ETA
Connecting to bin.entware.net (81.4.123.217:80)
libgcc_s.so.1        100% |***************************************************************************************************************************| 50840   0:00:00 ETA
Connecting to bin.entware.net (81.4.123.217:80)
libpthread-2.27.so   100% |***************************************************************************************************************************| 92648   0:00:00 ETA
Info: Basic packages installation...
Downloading http://bin.entware.net/armv7sf-k3.2/Packages.gz
Updated list of available packages in /opt/var/opkg-lists/entware
Installing busybox (1.28.3-2) to root...
Downloading http://bin.entware.net/armv7sf-k3.2/busybox_1.28.3-2_armv7-3.2.ipk
Installing libc (2.27-8) to root...
Downloading http://bin.entware.net/armv7sf-k3.2/libc_2.27-8_armv7-3.2.ipk
Installing libgcc (7.3.0-8) to root...
Downloading http://bin.entware.net/armv7sf-k3.2/libgcc_7.3.0-8_armv7-3.2.ipk
Installing libssp (7.3.0-8) to root...
Downloading http://bin.entware.net/armv7sf-k3.2/libssp_7.3.0-8_armv7-3.2.ipk
Installing librt (2.27-8) to root...
Downloading http://bin.entware.net/armv7sf-k3.2/librt_2.27-8_armv7-3.2.ipk
Installing libpthread (2.27-8) to root...
Downloading http://bin.entware.net/armv7sf-k3.2/libpthread_2.27-8_armv7-3.2.ipk
Configuring libgcc.
Configuring libc.
Configuring libpthread.
Configuring libssp.
Configuring librt.
Configuring busybox.
Installing entware-opt (227000-3) to root...
Downloading http://bin.entware.net/armv7sf-k3.2/entware-opt_227000-3_all.ipk
Installing libstdcpp (7.3.0-8) to root...
Downloading http://bin.entware.net/armv7sf-k3.2/libstdcpp_7.3.0-8_armv7-3.2.ipk
Installing entware-release (1.0-2) to root...
Downloading http://bin.entware.net/armv7sf-k3.2/entware-release_1.0-2_all.ipk
Installing zoneinfo-asia (2018e-1) to root...
Downloading http://bin.entware.net/armv7sf-k3.2/zoneinfo-asia_2018e-1_armv7-3.2.ipk
Installing zoneinfo-europe (2018e-1) to root...
Downloading http://bin.entware.net/armv7sf-k3.2/zoneinfo-europe_2018e-1_armv7-3.2.ipk
Installing findutils (4.6.0-1) to root...
Downloading http://bin.entware.net/armv7sf-k3.2/findutils_4.6.0-1_armv7-3.2.ipk
Installing terminfo (6.1-1) to root...
Downloading http://bin.entware.net/armv7sf-k3.2/terminfo_6.1-1_armv7-3.2.ipk
Installing locales (2.27-8) to root...
Downloading http://bin.entware.net/armv7sf-k3.2/locales_2.27-8_armv7-3.2.ipk
Installing grep (2.26-1) to root...
Downloading http://bin.entware.net/armv7sf-k3.2/grep_2.26-1_armv7-3.2.ipk
Installing libpcre (8.41-2) to root...
Downloading http://bin.entware.net/armv7sf-k3.2/libpcre_8.41-2_armv7-3.2.ipk
Installing opkg (2011-04-08-9c97d5ec-17b) to root...
Downloading http://bin.entware.net/armv7sf-k3.2/opkg_2011-04-08-9c97d5ec-17b_armv7-3.2.ipk
Installing entware-upgrade (1.0-1) to root...
Downloading http://bin.entware.net/armv7sf-k3.2/entware-upgrade_1.0-1_all.ipk
Configuring terminfo.
Configuring libpcre.
Configuring grep.
Configuring locales.
Entware uses separate locale-archive file independent from main system
Creating locale archive - /opt/usr/lib/locale/locale-archive
Adding en_EN.UTF-8
Adding ru_RU.UTF-8
You can download locale sources from http://pkg.entware.net/sources/i18n_glib227.tar.gz
You can add new locales to Entware using /opt/bin/localedef.new
Configuring entware-upgrade.
Upgrade operations are not required
Configuring opkg.
Configuring zoneinfo-europe.
Configuring zoneinfo-asia.
Configuring libstdcpp.
Configuring entware-release.
Configuring findutils.
Configuring entware-opt.
Info: Congratulations!
Info: If there are no errors above then Entware was successfully initialized.
Info: Add /opt/bin & /opt/sbin to your PATH variable
Info: Add '/opt/etc/init.d/rc.unslung start' to firmware startup script for Entware services to start

This is an alternative Entware installation. We recomend to install and setup Entware version of ssh server
and use it instead of a firmware supplied one. You can install dropbear or openssh as an ssh server
root@dlinkrouter:~#

Information source to develop these tools

The information comes from the router file system analysis. The router firmware available at ftp://ftp.dlink.eu/Products/dva/dva-5592/driver_software/ has been extracted using the binwalk (https://github.com/ReFirmLabs/binwalk) and jefferson (https://github.com/sviehb/jefferson) firmware extraction tools.

The file /usr/sbin/backup-conf.sh has been the main information source to build these tools.

To become root the main source of information has been the clish configuration files (the normal clish configuragion file /etc/clish/startup.xml and factory mode configuration file /etc/clish/prod/startup.xml) and startup scripts in /etc/init.d, especially /etc/init.d/services.sh.

YAPL file structure

Yapl files are used as the CGI templates. This is just documentation that I didn't know where else to put.

0x00 - 0x03: Header "Yapl"
0x04 - 0x07: Padding
0x08 - 0x0B: Number of strings
0x0C - 0x0F: Padding
0x10 - ....: Zero separated strings
.... - ....: Instructions that somehow reference the strings

Author

I am happy to be contacted about this project, my contact details are:

Item	Content
Author's name	Valerio Di Giampietro
Email	v@ler.io (yes it's a valid email address!)
Personal web site	http://va.ler.io (aka http://digiampietro.com)
LinkedIn	http://it.linkedin.com/in/digiampietro
Twitter	http://twitter.com/valerio
Facebook	http://facebook.com/digiampietro

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README.md

README.md

ADB Tools 2 description

Table of contents

Decrypt and modify the router configuration file

confedit

confbin2xml

confxml2bin

pkcrypt

How to become root on the D-Link DVA-5592 router

Get an unprivileged busybox command prompt

The role of the cm daemon running with root privileges

Exploiting the cm daemon to run a script with root privileges

hack-script.sh

Firmware modification kit

Firmware modification kit prerequisites

Content of the firmware modification kit folder (mod-kit)

Script mod-kit-configure.sh

Script mod-kit-run.sh

Entware installation

Information source to develop these tools

YAPL file structure

Author

Files

README.md

Latest commit

History

README.md

File metadata and controls

ADB Tools 2 description

Table of contents

Decrypt and modify the router configuration file

confedit

confbin2xml

confxml2bin

pkcrypt

How to become root on the D-Link DVA-5592 router

Get an unprivileged busybox command prompt

The role of the cm daemon running with root privileges

Exploiting the cm daemon to run a script with root privileges

hack-script.sh

Firmware modification kit

Firmware modification kit prerequisites

Content of the firmware modification kit folder (mod-kit)

Script mod-kit-configure.sh

Script mod-kit-run.sh

Entware installation

Information source to develop these tools

YAPL file structure

Author