VOIP Security Requires Layered Approach, Experts Say

A combination of technology and education helps address VOIP threats, security professionals say.

Security industry watchers say organizations need to take a layered approach to VOIP security.

Voice-over-IP deployments are expected by some to be targeted by attackers more as the number of organizations utilizing the technology increases, with phone phishing in particular becoming a greater threat. An example of a phone phishing scam would be an attacker sending a spoofed e-mail instructing the customer to call a phone number to reactivate his or her bank account.

When the customer calls, the customer is instructed to enter the account and or PIN number using the phone keypad-ultimately allowing the information to be harvested by the attacker.

"Voice is an inherently trusted communication and consumers are not conditioned to distrust the phone in the same manner that they do unsolicited e-mail," said Victoria Fodale, an analyst at research firm In-Stat.

Effectively combating VOIP threats requires applying the same best practices governing Internet security, she added.


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"For example, IP phones run operating systems and supporting software that make them susceptible to the same types of viruses, worms and malware that plague other computing devices," Fodale said. "As such, businesses will need to regularly assess vulnerabilities and deploy required patches and updates on this equipment."

She listed BorderWare Technologies and Sipera Systems as key providers of VOIP security tools on the infrastructure side, and Zfones encryption technology-which has been submitted to the IETF (Internet Engineering Task Force) as a proposed public standard-as important on the client side.

"Currently, most IP phones do not support encryption," she said. "But if encryption becomes standardized, SIP [Session Initiation Protocol] devices from different vendors will potentially be able to interoperate when encrypted voice calls are required."

Encryption is an issue because it is possible for someone to intercept the signaling and associated media streams of a conversation with VOIP.

"If you are using a voice-over-IP application to make a call over the Internet, then its possible for anybody who wants to to eavesdrop on that conversation ... because most of the voice-over-IP traffic is still not encrypted," said Paul Wood, an analyst with MessageLabs, headquartered in Gloucester, England.

However, he added, VOIP security threats remain largely theoretical, as hackers and cyber-thieves tend to focus their efforts on e-mail.

"One of the factors that we need to consider is that ... e-mail is certainly the single biggest target for [such attackers] because it enables them to exploit this massive ecosystem," Wood said, adding that the mix of hardware- and software-based VOIP deployments makes it harder for hackers to target systems.


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It takes a mix of security tools, from session border controllers to dedicated firewalls for VOIP traffic to network and host intrusion detection/prevention systems, to secure VOIP, Fodale said. She added that the key challenge for businesses will be to integrate VOIP security into a unified security framework.

"VOIP requires a system of protection that works across all clients and applications, servers and systems, to the network edge," she said. "In addition, the security components of this system should integrate with the existing security infrastructure."

To Steven Ostrowski, director of corporate communications for CompTIA (the Computing Technology Industry Association), based in Oakbrook Terrace, Ill., organizations need to spread awareness to the entire employee base if they hope to have truly secure VOIP environments. Decision makers and executive-level staff must become better informed about the real costs of security breaches and the real return on investment for both security training and certification, he said.

"The best security technology in the world wont work without appropriate human intervention, the skills of implementers and the vision of managers to properly deploy and apply it," Ostrowski said.

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