Dark Reading is part of the Informa Tech Division of Informa PLC

This site is operated by a business or businesses owned by Informa PLC and all copyright resides with them.Informa PLC's registered office is 5 Howick Place, London SW1P 1WG. Registered in England and Wales. Number 8860726.

Analytics

5/4/2006
04:45 AM
Connect Directly
Twitter
LinkedIn
RSS
E-Mail
50%
50%

Yes, Virginia, VOIP Can Be Secure

A live demo at Interop shows that with app-level gateways, deep packet inspection, and VPN, VOIP can be hardened from attack

One of the biggest knocks on VOIP technology is its lack of security. But at the Interop show this week, a group of vendors and technicians has quietly been demonstrating secure, multivendor VOIP connections -- both from within the LAN and from remote users over a VPN.

The InteropLabs VOIP demo focuses on two major areas of security: protecting the SIP gateway from attack and supporting remote users connecting via a VPN. The demo shows that it is possible to support VOIP within the closed confines of a single enterprise, though it also exposes potential problems with network address port translation (NAPT) that will need to be solved in live deployments.

In the demo, border protection starts with a SIP-aware application layer gateway or deep packet inspection. During call setup, the phones negotiate the call parameters they are willing to accept and what UDP ports, or ephemeral ports, they will use for voice packets. A non-SIP-aware firewall can't handle the ephemeral ports, and the voice connection between the phones could never be completed.

As Craig Johnson, systems engineering manager for Check Point, explains, "the SIP firewall has to be session-aware so that when a call ends -- either through a hang-up or a time-out -- the ephemeral ports are closed. Otherwise, avenues for malicious activity like toll fraud are possible."

The SIP-aware firewall also can stop denial-of-service attacks, which bombard the SIP gateway with registration and call requests, effectively cutting off legitimate calls or sending malformed SIP packets to the SIP gateway.

In addition to supporting ephemeral ports, SIP-aware firewalls and routers -- especially in remote offices -- must also be aware of NAPT, rewriting both the UDP packets and the network information in the SIP packets. Unlike IPSec, SIP offers no standards for NAPT traversal. In SIP networks, NAPT is achieved through packet rewriting or by changing routes within the receiving phone's network. The former is the less intrusive option.

What about encryption?
The InteropLabs VOIP demonstration used IPSec and an SSL VPN to encrypt the traffic between the remote user and central LAN, but it did not include encryption of SIP and voice traffic. The IETF has drafted some standards for encryption of SIP and RTP, and some products, including Sipera's IPCS310, support TLS and secure RTP. But vendors and other experts disagree on the immediate need for VOIP encryption.

Executives at Nortel acknowledge that encrypting VOIP eventually will be necessary. But as Aziz Khadbai, general manager of Converged Nortel Networks, observes, "VOIP installations today are within closed networks managed by a single entity. In the context of an internal network, the need for encryption is less critical than if the traffic passes over untrusted networks."

Robert Moskowitz, senior technical director at ICSA Labs, disagrees. "The CSI/FBI study shows that 80 percent of [VOIP] attacks are from insiders," he says. "Consider the ease of SIP hijacking and the ease of header manipulation. It's easy to become a man-in-the-middle and effectively wiretap all VOIP communications." Moskowitz cites an article on Voipinder entitled "Examining Two Well-Known Attacks on VOIP," which demonstrates such an attack.

Experts say the decision on whether to encrypt VOIP depends on how the VOIP travels over the network, the enterprise's need for security, and the state of the building's physical security.

— Mike Fratto, Editor at Large, Dark Reading

Organizations mentioned in this story

  • Check Point Software Technologies Ltd. (Nasdaq: CHKP)
  • Computer Security Institute (CSI)
  • ICSA Labs
  • Internet Engineering Task Force (IETF)
  • Nortel Networks Ltd. (NYSE/Toronto: NT)
  • Sipera Systems

    Mike Fratto is a principal analyst at Current Analysis, covering the Enterprise Networking and Data Center Technology markets. Prior to that, Mike was with UBM Tech for 15 years, and served as editor of Network Computing. He was also lead analyst for InformationWeek Analytics ... View Full Bio

    Comment  | 
    Print  | 
    More Insights
  • Comments
    Newest First  |  Oldest First  |  Threaded View
    News
    Former CISA Director Chris Krebs Discusses Risk Management & Threat Intel
    Kelly Sheridan, Staff Editor, Dark Reading,  2/23/2021
    Edge-DRsplash-10-edge-articles
    Security + Fraud Protection: Your One-Two Punch Against Cyberattacks
    Joshua Goldfarb, Director of Product Management at F5,  2/23/2021
    News
    Cybercrime Groups More Prolific, Focus on Healthcare in 2020
    Robert Lemos, Contributing Writer,  2/22/2021
    Register for Dark Reading Newsletters
    White Papers
    Video
    Cartoon Contest
    Write a Caption, Win an Amazon Gift Card! Click Here
    Latest Comment: This comment is waiting for review by our moderators.
    Current Issue
    2021 Top Enterprise IT Trends
    We've identified the key trends that are poised to impact the IT landscape in 2021. Find out why they're important and how they will affect you today!
    Flash Poll
    Building the SOC of the Future
    Building the SOC of the Future
    Digital transformation, cloud-focused attacks, and a worldwide pandemic. The past year has changed the way business works and the way security teams operate. There is no going back.
    Twitter Feed
    Dark Reading - Bug Report
    Bug Report
    Enterprise Vulnerabilities
    From DHS/US-CERT's National Vulnerability Database
    CVE-2021-25284
    PUBLISHED: 2021-02-27
    An issue was discovered in through SaltStack Salt before 3002.5. salt.modules.cmdmod can log credentials to the info or error log level.
    CVE-2021-3144
    PUBLISHED: 2021-02-27
    In SaltStack Salt before 3002.5, eauth tokens can be used once after expiration. (They might be used to run command against the salt master or minions.)
    CVE-2021-3148
    PUBLISHED: 2021-02-27
    An issue was discovered in SaltStack Salt before 3002.5. Sending crafted web requests to the Salt API can result in salt.utils.thin.gen_thin() command injection because of different handling of single versus double quotes. This is related to salt/utils/thin.py.
    CVE-2021-3151
    PUBLISHED: 2021-02-27
    i-doit before 1.16.0 is affected by Stored Cross-Site Scripting (XSS) issues that could allow remote authenticated attackers to inject arbitrary web script or HTML via C__MONITORING__CONFIG__TITLE, SM2__C__MONITORING__CONFIG__TITLE, C__MONITORING__CONFIG__PATH, SM2__C__MONITORING__CONFIG__PATH, C__M...
    CVE-2021-3197
    PUBLISHED: 2021-02-27
    An issue was discovered in SaltStack Salt before 3002.5. The salt-api's ssh client is vulnerable to a shell injection by including ProxyCommand in an argument, or via ssh_options provided in an API request.