Chapter

Understanding Security Features for Cisco Unified IP Phones

Table 1-4

Overview of Security Features (continued)

 

 

 

Feature

 

Description

 

 

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

Implements parts of the certificate generation procedure that are too

Function)

 

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 1-13for more information.

 

 

Encrypted configuration files

Lets you ensure the privacy of phone configuration files.

 

 

Optional disabling of the web server

You can prevent access to a phone’s web page, which displays a variety of

functionality for a phone

operational statistics for the phone. See the “Disabling and Enabling Web Page

 

 

Access” section on page 8-3.

 

 

 

 

Cisco Unified IP Phone 8941 and 8945 Administration Guide for Cisco Unified Communications Manager 8.5 (SCCP and SIP)

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Cisco Systems 8941, 8945 manual Security Profiles section on page 1-13for more information, Access section on