Grandstream Networks GXV3370 User manual

Grandstream Networks, Inc.
GXV3370
IP Multimedia Phone for AndroidTM
Security Guide

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GXV3370 Security Guide
Table of Contents
OVERVIEW.....................................................................................................................3
WEB UI/SSH ACCESS ...................................................................................................4
GXV3370 Web UI Access.....................................................................................................................4
Web UI Access Protocols .....................................................................................................................4
User Login ............................................................................................................................................4
User Management Levels ....................................................................................................................5
SSH Access..........................................................................................................................................6
DEVICE CONTROL SECURITY .....................................................................................8
Configuration via Keypad Menu ...........................................................................................................8
Permission to Install/Uninstall Apps .....................................................................................................8
GUI Config Tool Settings ......................................................................................................................9
SECURITY FOR SIP ACCOUNTS AND CALLS ..........................................................10
Protocols and Ports ............................................................................................................................10
Anonymous/Unsolicited Calls Protection ...........................................................................................12
SRTP ..................................................................................................................................................13
NETWORK SECURITY.................................................................................................15
OpenVPN®..........................................................................................................................................15
802.1X ................................................................................................................................................16
Bluetooth ............................................................................................................................................16
PC Port Mode .....................................................................................................................................16
SECURITY FOR GXV3370 SERVICES ........................................................................18
Provisioning via Configuration File .....................................................................................................18
Firmware Upgrading ...........................................................................................................................20
TR-069................................................................................................................................................21
FTP Server .........................................................................................................................................22
ADB Service .......................................................................................................................................22
LDAP ..................................................................................................................................................23
Syslog.................................................................................................................................................23
SECURITY GUIDELINES FOR GXV3370 DEPLOYMENT ..........................................25

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Table of Figures
Figure 1: Web UI Access Settings.................................................................................................................4
Figure 2: GXV3370 Web UI Login.................................................................................................................5
Figure 3: GXV3370 Admin Password Change..............................................................................................5
Figure 4: Admin (left) and User (right) Web Access......................................................................................6
Figure 5: SSH Access on GXV3370 .............................................................................................................7
Figure 6: Limit Access to Advanced Settings and Apps on LCD...................................................................8
Figure 7: Cust File Provision Page ...............................................................................................................9
Figure 8: Configure TLS as SIP Transport ..................................................................................................10
Figure 9: SIP TLS Settings on GXV3370 ....................................................................................................11
Figure 10: Additional SIP TLS Settings ....................................................................................................... 11
Figure 11: Settings to Block Anonymous Call .............................................................................................12
Figure 12: Settings to Block Unwanted Calls..............................................................................................13
Figure 13: SRTP Settings ...........................................................................................................................14
Figure 14: OpenVPN® Settings ...................................................................................................................15
Figure 15: OpenVPN® for Secure Network Access.....................................................................................15
Figure 16: 802.1X Settings..........................................................................................................................16
Figure 17: 802.1X for GXV3370 Deployment .............................................................................................16
Figure 18: GXV3370 PC Port Mode............................................................................................................17
Figure 19: GXV3370 Config File Provisioning ............................................................................................18
Figure 20: Validate Certification Chain........................................................................................................19
Figure 21: Certificate Management.............................................................................................................19
Figure 22: GXV3370 Firmware Upgrade Configuration ..............................................................................20
Figure 23: Validate Certification Chain........................................................................................................20
Figure 24: Certification Management ..........................................................................................................21
Figure 25: TR-069 Connection Settings Page ............................................................................................21
Figure 26: FTP Service On .........................................................................................................................22
Figure 27: Access Device through ADB ......................................................................................................22
Figure 28: GXV3370 LDAP Settings ...........................................................................................................23
Figure 29: Syslog Protocol ..........................................................................................................................24

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GXV3370 Security Guide
OVERVIEW
This document presents a summary of security measures, factors, and configurations that users are
recommended to consider when configuring and deploying the GXV3370.
Note: We recommend using the latest firmware for latest security patches.
The following sections are covered in this document:
•Web UI/SSH Access
Web UI access is protected by username/password and login timeout. Two-level user management is
configurable. SSH access is supported for mainly troubleshooting purpose and it’s recommended to disable
it in normal usage.
•Device Control Security
The GXV3370 has multiple ways to limit the use for network settings, apps, and other settings if not
necessary for the end user.
•Security for SIP Accounts and Calls
The SIP accounts use specific port for signaling and media stream transmission. It also offers configurable
options to block anonymous calls and unsolicited calls.
•Network Security
The GXV3370 supports OpenVPN, 802.1X, Bluetooth and PC port for network access. OpenVPN secures
remote connection and 802.1X provides network access control. For Bluetooth and PC port, it’s
recommended to turn them off if not used.
•Security for GXV3370 Services
GXV3370 supports service such as HTTP/HTTPS/TFTP provisioning, TR-069, LDAP, as well as allows
ADB and FTP access. For provisioning, we recommend using HTTPS with username/password and using
password-protected XML file. For services such as ADB and FTP, we recommend disabling them if not
used to avoid potential port exposure.
•Deployment Guidelines for GXV3370
This section introduces protocols and ports used on GXV3370 and recommendations for routers/firewall
settings.
This document is subject to change without notice.
Reproduction or transmittal of the entire or any part, in any form or by any means, electronic or print, for
any purpose without the express written permission of Grandstream Networks, Inc. is not permitted.

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GXV3370 Security Guide
WEB UI/SSH ACCESS
GXV3370 Web UI Access
The GXV3370 embedded web server responds to HTTP/HTTPS GET/POST requests. Embedded HTML
pages allow users to configure the device through a web browser such as Microsoft IE, Mozilla Firefox,
Google Chrome and etc. With this, administrators can access and configure all available GXV3370
information and settings. It is critical to understand the security risks involved when placing the GXV3370
phone on public networks and it’s recommended not to do so.
Web UI Access Protocols
HTTP and HTTPS are supported to access the GXV3370 web UI and can be configured under web UI →
System Settings → Security Settings → Web/SSH Access. To secure transactions and prevent
unauthorized access, it is highly recommended to:
1. Use HTTPS instead of HTTP.
2. Avoid using well known port numbers such as 80 and 443.
Figure 1: Web UI Access Settings
User Login
Username and password are required to log in the GXV3370 web UI.

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Figure 2: GXV3370 Web UI Login
The factory default username is “admin” and the default password is “admin”. The GXV3370 web UI require
to change the default password at first time login.
Figure 3: GXV3370 Admin Password Change
To change the password for default user "admin", navigate to System Settings → Security Settings → User
Info Management. The password length must between 6 and 32 characters. Strong password with a
combination of numbers, uppercase letters, lowercase letters, and special characters is always
recommended for security purpose.
User Management Levels
Two user privilege levels are currently supported:
•Admin
•User

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Admin login has access to all of the GXV3370’s web UI pages and can execute all available operations.
User login has limited access to the web UI pages. With user login, the user is not allowed to configure the
following settings:
•Account Settings
•Phone Settings → General Settings / Ringtone / Video Settings
•Network Settings → Advanced Network Settings
•System Settings → TR069
•Maintenance → Upgrade / Event Notification
•Value-added Service
Even user login can access certain web UI pages, it has less options compared to admin login, such as in
System Settings → Security Settings page.
It is recommended to keep admin login with administrator only. And end user should be provided with user-
level login only, if web UI access is needed.
Figure 4: Admin (left) and User (right) Web Access
SSH Access
The GXV3370 allows access via SSH for advanced troubleshooting purpose. This is usually not needed
unless the administrator or Grandstream support needs it for troubleshooting purpose. SSH access on
GXV3370 is enabled by default with port 22 used. It’s recommended to disable it for daily normal usage. If
SSH access needs to be enabled, changing the port to a different port other than the well-known port 22 is
a good practice.

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Figure 5: SSH Access on GXV3370

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DEVICE CONTROL SECURITY
From GXV3370 web UI → System Settings → Security Settings → Web/SSH Access, administrator can set
whether the user can use specific features or install apps from LCD, shown as below.
Figure 6: Limit Access to Advanced Settings and Apps on LCD
Configuration via Keypad Menu
This option configures access for keypad Menu settings on the Settings interface of the phone. It is
recommended to use “Constraint Mode” for end users.
•Unrestricted:
Configure all settings on the LCD settings interface.
•Basic Settings Only:
Advanced Settings, Wireless & Network options will not be displayed in LCD settings menu.
•Basic Settings & Network Settings:
Advanced Settings option will not be displayed in LCD settings menu.
•Constraint Mode:
The user is required to enter the correct admin password to access Wireless & Network options and
Advanced Settings.
Permission to Install/Uninstall Apps
This option configures the permission for users to install/uninstall 3rd party applications. “Unknown Sources”
setting is under LCD → Settings → Basic → Security Settings. It is recommended to use “Not allow” if the
device is used at public properties.
•Allow:
The user can install/uninstall any 3rd party apps as needed.
•Require admin password:
The user needs to enter the correct admin password before he/she can install/uninstall 3rd party apps.

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•Require admin password if the app source is unknown:
The user needs to enter the correct admin password only when installing apps from unknown source.
Admin password is also required when the user uninstalls the 3rd party apps.
•Not allow:
The user cannot install/uninstall third-party apps. Unknown sources setting is not available under this
mode.
GUI Config Tool Settings
The GUI config tool is an online tool designed to customize the configuration for devices. Here is the link
to the GUI config tool:
http://tools.grandstream.com:8081
From there, the administrator can build a customized file to remove access for certain apps and task bar
features. The tool would generate a file “gxv3370cust” which should be uploaded to a HTTP/TFTP server.
Then the user needs to configure the server address as GUI Customization File URL under web UI →
Maintenance → Upgrade → Config File to download the file to GXV3370. For more details, please refer to
the guide:
http://www.grandstream.com/sites/default/files/Resources/GXV3370_GUI_Customization_Web_Tool_Gui
de.pdf
Figure 7: Cust File Provision Page

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SECURITY FOR SIP ACCOUNTS AND CALLS
Protocols and Ports
By default, after factory reset, the SIP account 1 is active. Since the default local SIP port is 5060 for account
1, this allows user to make direct IP call even if the account is not registered to any PBX. If the user is not
using any account, it is recommended to uncheck the settings from web UI → Account → General Settings
→ Account Active to deactivate account 1.
Below are the ports/protocols used on GXV3370 SIP accounts. GXV3370 supports up to 16 SIP accounts.
•SIP transport protocol:
The GXV3370 supports SIP transport protocol “UDP” “TCP” and “TLS”. By default, it’s set to “UDP”. It’s
recommended to use “TLS” so the SIP signaling is encrypted. SIP transport protocol can be configured
per SIP account under web UI → Account → Account x → SIP Settings. When “TLS” is used, we
recommend using “sips” instead of “sip” for SIP URI scheme to ensure the entire SIP transaction is
secured instead of “best-effort”.
Figure 8: Configure TLS as SIP Transport
SIP TLS certificate, private key and password can be configured under GXV3370 web UI→System
Settings→Security Settings→SIP TLS.

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Figure 9: SIP TLS Settings on GXV3370
When SIP TLS is used, the GXV3370 also offers additional configurations to check domain certificate
and validate certificate chain. These settings can be found under web UI → Account → Account x →
Advanced Settings.
- Check Domain Certificate:
If enabled, the GXV3370 will check the domain certificate when TLS/TCP is used for SIP transport.
The default setting is “No”.
- Validate Certification Chain:
If enabled, the GXV3370 will validate server’s certification chain when TLS/TCP is used for SIP
transport. The default setting is “No”.
Figure 10: Additional SIP TLS Settings

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•Local SIP port when using UDP/TCP:
Starting from 5060 for account 1, the port numbers increase by 2 for account x. For example, 5062 is
the default local SIP port for account 2, 5064 for account 3, etc. The local SIP port can be configured
under Account→SIP Settings for each SIP account.
•Local SIP port when using TLS:
The SIP TLS port is the UDP SIP port plus 1. For example, if account 1’s SIP port is 5060, its TLS port
would be 5061.
•Local RTP port:
The default port value is 50040. Below is the range the GXV3370 uses for different RTP from web UI
→ Phone Settings → General Settings. (N is from 0 to 15, representing SIP account 1 to 16).
Audio RTP port: Port_Value+10*N
Audio RTCP port: Port_Value+10*N+1
Video RTP port: Port_Value+10*N+2
Video RTCP port: Port_Value+10*N+3
FEC RTP port: Port_Value+10*N+4
FEC RTCP port: Port_Value+10*N+5
BFCP Protocol port: Port_Value+10*N+6
BFCP RTP port: Port_Value+10*N+8
BFCP RTCP port: Port_Value+10*N+9
Anonymous/Unsolicited Calls Protection
If the user would like to have anonymous calls blocked, please go to GXV3370 web UI → Account →
Account x → Call Settings and enable option “Intercept Anonymous Calls”. This will automatically block the
SIP call if the caller ID is anonymous.
Figure 11: Settings to Block Anonymous Call
Additionally, the GXV3370 has built-in mechanism that detects and stops the spam SIP calls from ringing
the phones. Please see below web UI → Account → Account x → Advanced Settings. It is recommended
to enable highlighted options to validate incoming SIP requests.

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Figure 12: Settings to Block Unwanted Calls
- Only Accept SIP Requests from Known Servers:
When set to “Yes”, the GXV3370 will answer the SIP request from saved servers and only the SIP
requests from saved servers will be accepted. The SIP requests from the unregistered server will be
rejected. The default setting is “No”.
- Check SIP User ID for Incoming INVITE:
This configures the GXV3370 to check the SIP User ID in the Request URI of the SIP INVITE message
from the remote party. If it doesn't match the phone's SIP User ID, the call will be rejected. The default
setting is “No”.
- Authenticate Incoming INVITE:
This configures the GXV3370 to authenticate the SIP INVITE message from the remote party. If set to
"Yes", the phone will challenge the incoming INVITE for authentication with SIP 401 Unauthorized
response. The default setting is "No".
- SIP Realm Used for Challenge INVITE & NOTIFY:
Configure this item to validate incoming INVITE and NOTIFY. To use this feature, “Authenticate
Incoming INVITE” must be enabled first for it to take effect for INVITE. For NOTIFY, “SIP NOTIFY
Authentication” must be enabled first under web UI → Maintenance → Upgrade → Advanced Settings.
The SIP NOTIFY message information for the provision includes check- sync, resync and reboot.
SRTP
To protect voice communication from eavesdropping, the GXV3370 phones support SRTP for media traffic
using AES 128&256. It is recommended to use SRTP if server supports it. SRTP can be configured in web
UI → Account → Codec Settings.

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Figure 13: SRTP Settings

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NETWORK SECURITY
OpenVPN®
GXV3370 supports OpenVPN®and by default it’s disabled. It can be enabled and used for secure remote
connection. If the device is using OpenVPN®to access network, it is recommended to use a different port
other than the default well-known port 1194 for added security. Please see OpenVPN®related settings
shown as below from web UI →Network Settings →OpenVPN®Settings.
Figure 14: OpenVPN® Settings
Figure 15: OpenVPN® for Secure Network Access

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802.1X
GXV3370 supports EAPOL where access to switchports can be controlled with identity/password and
certificate. By default, it’s disabled. When it’s enabled, there are 3 different mode for selection: EAP-MD5,
EAP-TLS and EAP-PEAP. Network administrators can set this up accordingly for media access control and
network security purpose.
Figure 16: 802.1X Settings
Figure 17: 802.1X for GXV3370 Deployment
Bluetooth
GXV3370 supports Bluetooth for Bluetooth headset connection, file transferring and handsfree mode for
cell phones. By default, Bluetooth is disabled and it can be enabled from LCD. If there is no Bluetooth
device used with GXV3370, it’s recommended to turn off Bluetooth so it’s not discoverable by nearly
Bluetooth devices.
PC Port Mode
GXV3370 has dual switched 10/100/1000Mbps ports. LAN port is for network access and PC port has
multiple mode. Assuming GXV3370 has network access, PC port mode has the following settings:

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- When the PC port mode is set to “Enabled”, another network device can obtain network access by
connecting to GXV3370’s PC port. The PC VLAN tag and PC priority values are only available when
the port mode is set to "Enabled".
- When the PC port mode is set to "Mirrored", the data packet sent and received by the phone would go
through the LAN port and PC port at the same time. In this case, PC port is only used for capturing
debugging packets and unable to support network data exchange.
- If the administrator or user does not plan to use PC port for network device access or troubleshooting
purpose, it is recommended to set PC port mode to “Disable” so any connection through it will be
rejected.
Figure 18: GXV3370 PC Port Mode

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GXV3370 Security Guide
SECURITY FOR GXV3370 SERVICES
Provisioning via Configuration File
GXV3370 supports downloading configuration file via HTTP/HTTPS/TFTP. Below figure shows the options
for config file provisioning.
Figure 19: GXV3370 Config File Provisioning
We recommend users to consider the following options for added security when deploying the GXV3370
with provisioning.
- Config Upgrade Via: HTTPS:
By default, HTTPS is selected. This is recommended so the traffic is encrypted while travelling through
the network.
- HTTP/HTTPS User Name and Password:
This can be set up as required on the provisioning server when HTTP/HTTPS is used. Only when the
GXV3370 has the correct username and password configured, it can be authenticated by the
provisioning server and the config file can be downloaded.
- Authenticate Config file:
This sets the GXV3370 to authenticate configuration file before applying it. When set to “Yes”, the
configuration file must include P value P1 with GXV3370’s administration password. If it is missed or
does not match the password, the GXV3370 will not apply the config file.

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- XML Config File Password:
The GXV3370 XML config file can be encrypted using OpenSSL. When it’s encrypted, the GXV3370
must supply the correct password in this field so it can decrypt XML configuration file after downloading
it. Then the configuration can be applied to the GXV3370. Please note this feature is supported on XML
config file instead of the binary config file. Therefore, it’s recommended to use XML config file format
and encrypt it with this feature.
- Validate Certificate Chain:
This configures whether to validate the server certificate when downloading the firmware/config file. If
set to "Yes", the phone will download the firmware/config file only from the legitimate server.
Figure 20: Validate Certification Chain
GXV3370 supports uploading CA certificate to validate the server certificate and this setting is under
GXV3370 web UI → System Settings → Security Settings → Certificate Management.
Figure 21: Certificate Management