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Cisco Unified IP Phone Administration Guide for Cisco Unified Communications Manager 8.5
OL-23092-01
Chapter 1 An Overview of the Cisco Unified IP Phone
Understanding Security Features for Cisco Unified IP Phones
Table 1-4
Overview of Security Features
Feature
Description
Image authentication
Signed binary files (with the extension .sbn) prevent tampering with the firmware
image before it is loaded on a phone. Tampering with the image causes a phone to
fail the authentication process and reject the new image.
Customer-site certificate installation
Each Cisco Unified IP Phone requires a unique certificate for device
authentication. Phones include a manufacturing installed certificate (MIC), but for
additional security, you can specify in Cisco Unified Communications Manager
Administration that a certificate be installed by using the CAPF (Certificate
Authority Proxy Function). Alternatively, you can install an LSC from the Security
Configuration menu on the phone. See
Configuring Security on the Cisco Unified
IP Phone, page 3-16
for more information.
Device authentication
Occurs between the Cisco Unified Communications Manager server and the phone
when each entity accepts the certificate of the other entity. Determines whether a
secure connection between the phone and a Cisco Unified Communications
Manager should occur, and, if necessary, creates a secure signaling path between
the entities using TLS protocol. Cisco Unified Communications Manager does not
register phones unless they can be authenticated by the
Cisco Unified Communications Manager.
File authentication
Validates digitally signed files that the phone downloads. The phone validates the
signature to make sure that file tampering did not occur after the file creation. Files
that fail authentication are not written to Flash memory on the phone. The phone
rejects such files without further processing.
Signaling Authentication
Uses the TLS protocol to validate that no tampering has occurred to signaling
packets during transmission.
Manufacturing installed certificate
Each Cisco Unified IP Phone contains a unique manufacturing installed certificate
(MIC), which is used for device authentication. The MIC is a permanent unique
proof of identity for the phone, and allows Cisco Unified Communications
Manager to authenticate the phone.
Secure SRST reference
After you configure a SRST reference for security and then reset the dependent
devices in Cisco Unified Communications Manager Administration, the TFTP
server adds the SRST certificate to the phone cnf.xml file and sends the file to the
phone. A secure phone then uses a TLS connection to interact with the
SRST-enabled router.
Media encryption
Uses SRTP to ensure that the media streams between supported devices proves
secure and that only the intended device receives and reads the data. Includes
creating a media master key pair for the devices, delivering the keys to the devices,
and securing the delivery of the keys while the keys are in transport.
Signaling encryption
Ensures that all SCCP and SIP signaling messages that are sent between the device
and the Cisco Unified Communications Manager server are encrypted.
CAPF (Certificate Authority Proxy
Function)
Implements parts of the certificate generation procedure that are too
processing-intensive for the phone, and it interacts with the phone for key
generation and certificate installation. The CAPF can be configured to request
certificates from customer-specified certificate authorities on behalf of the phone,
or it can be configured to generate certificates locally.
Security profiles
Defines whether the phone is nonsecure, authenticated, encrypted, or protected.
See
Understanding Security Profiles, page 1-16
for more information.
