SIP Security in Yate

SIP secure uses TLS protocol for securing the signalling. This will stop man in the middle attacks and hide the called identity.

In order to secure the media SRTP protocol is used. This will add confidentiality, message authentication, and replay protection to the RTP data.

How to configure SIP secure

Yate can bind on TLS. This is done using a listener, that it is a specific section in ysipchan.conf, that will specify to which network interface Yate will listen.

In the next steps will configure Yate to bind on TLS and to use SRTP packets for voice.

How to set a TLS listener

In ysipchan.conf:

[general]
type=tls
addr=x.x.x.x
port=5061
sslcontext=server_context

Configure a SSL server context

In openssl.conf

[server_context]
enable=yes
certificate=name.crt
key=name.key

The files name.crt and name.key have to be in the same place as the configuration file in this example.

Enable SRTP

Data security protocols such as SRTP rely upon a separate key management system to securely establish encryption and/or authentication keys. TLS will protect the SDP message.

In ysipchan.conf by default secure parameter is disabled, for using SRTP you have to enable it.

[default]
; secure: bool: Generate and accept RFC 4568 security descriptors for SRTP
secure=enable

Advantages

• SRTP is ideal for protecting Voice over IP traffic because it can be used in conjunction with header compression and has no effect on IP Quality of Service.
• SRTP provide significant advantages, especially for voice traffic using low-bitrate voice codecs such as G.729 and iLBC.
• SRTP confidentiality of RTP packets protects packet payloads from being read by entities without the secret encryption key.
• SRTP message authentication of RTP packets protects the integrity of a packet against forgery, alteration, or replacement.
• TLS provide privacy and data integrity between communicating applications.

See also

• Transport Layer Security
• SIP Configuration File
• Telephony