1-17
Cisco Unified IP Phone 6921, 6941, 6945, and 6961 Administration Guide for Cisco Unified Communications Manager 8.5 (SCCP and SIP)
OL-23769-01
Chapter
Understanding Security Features for Cisco Unified IP Phones
Device authentication Occurs between the Cisco Unified CM 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 CM should occur; and, if
necessary, creates a secure signaling path between the entities by using TLS
protocol. Cisco Unified CM will not register phones unless they can be
authenticated by the Cisco Unified CM.
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 CM
to authenticate the phone.
Secure SRST reference After you configure a SRST reference for security and then reset the dependent
devices in Cisco Unified CM 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 signaling messages that are sent between the device and
the Cisco Unified CM server are encrypted.
CAPF (Certificate Authority Proxy
Function) Implements parts of the certificate generation procedure that are too
processing-intensive for the phone, and 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 or encrypted. See the “Understanding
Security Profiles” section on page 1-18 for more information.
Encrypted configuration files Lets you ensure the privacy of phone configuration files.
Optional disabling of the web server
functionality for a phone You can prevent access to a phone’s web page, which displays a variety of
operational statistics for the phone. See the “Disabling and Enabling Web Page
Access” section on page 8-3.
Table 1-6 Overview of Security Features (continued)
Feature Description