ZTE ADSL ZXV10 W300 Modems - Multiple Vulnerabilities

# Exploit Title: [ZTE ADSL ZXV10 W300 modems - Multiple vulnerabilities]
# Discovered by: Karn Ganeshen
# Vendor Homepage: [www.zte.com.cn]
# Versions Reported: [W300V2.1.0f_ER7_PE_O57 and W300V2.1.0h_ER7_PE_O57]

*CVE-ID*:
CVE-2015-7257
CVE-2015-7258
CVE-2015-7259

*Note*: Large deployment size, primarily in Peru, used by TdP.

1 *Insufficient authorization controls*
*CVE-ID*: CVE-2015-7257
Observed in Password Change functionality. Other functions may be
vulnerable as well.

*Expected behavior:*
Only administrative 'admin' user should be able to change password for all
the device users. 'support' is a diagnostic user with restricted
privileges. It can change only its own password.

*Vulnerability:*
Any non-admin user can change 'admin' password.

*Steps to reproduce:*
a. Login as user 'support' password XXX
b. Access Password Change page - http://<IP>/password.htm
c. Submit request
d. Intercept and Tamper the parameter ­ username ­ change from 'support' to
'admin'
e. Enter the new password ­> old password is not requested ­> Submit
> Login as admin
-> Pwn!


2 *Sensitive information disclosure - clear-text passwords*
*CVE-ID*: CVE-2015-7258
Displaying user information over Telnet connection, shows all valid users
and their passwords in clear­-text.

*Steps to reproduce:*
$ telnet <IP>
Trying <IP>...
Connected to <IP>.
Escape character is '^]'.
User Access Verification
Username: admin
Password: <­­­ admin/XXX1

$sh
ADSL#login show                 <--­­­ shows user information
Username Password Priority
admin        password1 2
support      password2 0
admin         password3 1

3 *(Potential) Backdoor account feature - **insecure account management*
*CVE-ID*: CVE-2015-7259
Same login account can exist on the device, multiple times, each with
different priority#. It is possible to log in to device with either of the
username/password combination.

It is considered as a (redundant) login support *feature*.

*Steps to reproduce:*
$ telnet <IP>
Trying <IP>...
Connected to <IP>.
Escape character is '^]'.
User Access Verification
User Access Verification
Username: admin
Password: <­--­­ admin/password3

$sh
ADSL#login show
Username  Password  Priority
admin  password1  2
support  password2  0
admin  password3  1

+++++
-- 
Best Regards,
Karn Ganeshen