NIST offers guidelines for securing VOIP

Voice over IP technology offers potential cost savings and increased functionality, but it also may introduce new security headaches for systems administrators, the National Institute of Standards and Technology has warned.

"VOIP adds a number of complications to existing network technology, and these problems are magnified by security considerations," the agency said in a draft version of security guidelines released today for public comment.

Special Publication 800-58, Security Considerations for Voice Over IP Systems, is available online. Comments on the draft will be accepted until June 18.

Firewalls can delay or block call setups, and encryption can introduce unacceptable latency. Putting voice on data networks opens new potential avenues for attacks to the data network, and Network Address Translation complicates the process.

"VOIP is still an emerging technology," NIST said, and agencies considering it should carefully assess their understanding of the technology and the associated risks, and the maturity of both their IT and physical security. Because anyone with physical access to the LAN could potentially monitor voice traffic, access control to network elements is critical.

NIST recommends:

• Separating voice and data traffic on logically different networks


• Denying access to the voice gateway from the data network


• Using firewalls designed for VOIP traffic


• Using IPsec or Secure Shell as well as strong authentication for remote management and auditing


• Encrypting voice traffic at the router or gateway if performance is a problem. Newer IP phones are able to handle Advanced Encryption Standard algorithms. Federal Information Processing Standard 140-2 certification is required for federal use.