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How secure is SIP?

Voice over Internet Protocol (VoIP) network, like all other things on the internet, is venerable to security threats. The decision to move to a better and cheaper telecommunication option is very wise. However, you need to pay equal attention to the security of the phone system as well.

Wavetel’s Secure SIP Trunks
How secure is SIP?
Tooba Altaf author , Friday January 22, 2016

Voice over Internet Protocol (VoIP) network, like all other things on the internet, is venerable to security threats. The decision to move to a better and cheaper telecommunication option is very wise. However, you need to pay equal attention to the security of the phone system as well.

The Session Initiation Protocol (SIP) is used widely for making VoIP calls because of its simple and easy design and functionality as compared to other alternatives like H.323, MGCP, and MEGACO. Unfortunately, SIP is not a secure option and it may expose your network to a number of security issues.

Insecure SIP means:

If you are wondering about the security risks that an organization might get involved in by using unsecured SIP, here is a glimpse of all those security threats;

  • Eavesdropping: attackers may get unauthorized access to the calls.
  • Viruses and bugs: attackers may send unwanted viruses or bugs to the targeted network.
  • Re-transmission: attackers may re-transmit the messages to the third party.
  • Message Tampering: attackers may tamper with the messaging, affecting its integrity.
  • Access denied to network: attackers can prevent the access to the network by flooding SIP servers.
  • Impersonation: attackers can control VoIP network and make fake calls on behalf of the company.

In order to put things in perspective, let us give you a real life example. The CEO of the company is discussing major HR policies with the HR manager over the phone. The employee working in the IT department can easily access their phone call and become privy to top secret information.

However, the good news is the SIP security threats are exaggerated and over-hyped. Also, there are many ways to make SIP secure.

How to make SIP secure:

  • Transport Layer Security (TLS)

SIP messages are easier to hack because they are transmitted via TCP or UDP connections. A secure SIP uses Transport Layer Security (TLS) for authentication.

TLS basically encrypts the channel used for sending SIP messages, indirectly encrypting the whole SIP session. The call initiation and data packet transfer require authentication from end users (user-to-user).

TLS requires the client to make a TLS connection with the server in order to begin exchanging encrypted SIP messages.

A session key is generated each time a caller successfully connects with the receiver, which encrypts and decrypts the data throughout the call.

Secure Real-time Transport Protocol (SRTP):

SIP messages can also be protected by SRTP. It is an ideal way to safeguard an SIP session and all the media shared during it since it never interferes with the Quality of Service. The main security functions of SRTP is “confidentiality, message authentication, and replay protection”.

The success of SRTP is that it creates a unique stream for each Real-time Transport Protocol (RTP) packet shared during an SIP session. This way, the attackers are not able to find or track the original RTP.

The Verdict:

There is no denying the fact that SIP has security vulnerabilities. However, the risks are not too complex and can be handled. There are practical ways available to make the SIP secure enough to function in a corporate world. Here much benefits of SIP Trunks.

Best SIP Trunks | Wavetel