Securing The Distributed Network Perimeter

The corporate network perimeter is not what is used to be.

A decade ago, companies focused on securing the perimeter, making sure that the inside of the network remained a safe, trusted environment, while attempting to create a digital wall to keep out the Internet vandals. Security professionals realized over time that defense in-depth should extend within the network because attackers inevitably get inside. In addition, with employees bringing in mobile devices and nomadic employees working from a variety of unsecured locations outside of the corporate network, the definition of the perimeter has changed.

Analysts and some security firms talked about the end of the perimeter, coining the abstruse term "deperimeterization." Instead of going away, however, an organization's security perimeter has simply become more distributed, says Jody Brazil, president and chief technology officer of FireMon, a configuration and policy management firm.

"Instead of thinking about a big circle around your entire enterprise, you need to start thinking about little circles around critical elements of your network -- a little circle around your data center, a little circle around your point-of-sale systems, and a little circle around your mobile users," he says. "Instead of one big perimeter, you end up with these smaller segmentations -- you can think of them as mini-perimeters."

Securing those mini-perimeters is a daunting task. Companies no longer have a single electronic wall dividing "us" and "them," but must place and maintain security controls across myriad branch offices and wherever their increasingly mobile employees roam.

Large enterprises have the resources to build the security infrastructure to deal with the distributed perimeter. Small and midsize companies often rely on services, traditionally from managed service providers, but increasingly from cloud security services as well.

Cloud security services can help companies deal with the increasing use of mobile devices and cloud services for business. Requiring a mobile user to connect back to the corporate firewall using a virtual private network may give a company greater control over their use of corporate resources, but at the cost of a slower connection and inefficiency that may dissuade employees from using the secure method of access.

[With cloud services collecting more data from businesses, firms should prepare for potential breaches that involve their providers. See Enterprises Should Practice For Cloud Security Breaches.]

Cloud security services aimed at offering clean networks to mobile users -- such as Zscaler and OpenDNS -- as well as more traditional endpoint security software that use the cloud to distributed threat intelligence, updates, and security policies, can help extend the perimeter to mobile devices.

"You have to carefully evaluate the operational concerns and security concerns before you move a business function to the cloud," says Nimmy Reichenberg, vice president of marketing and business development for AlgoSec, a security-policy management provider. "URL filtering is a good example of a function that makes sense to move the cloud."

Along with e-mail security and Web security, integrating identity and access management between the internal network and the cloud is another growth area of cloud security services, according to analyst firm Gartner. In 2013, cloud security services accounted for $2.1 billion in global revenue, in part because of the growth in IAM services.

Managing the devices that maintain the corporate network perimeter -- the firewalls and intrusion detection systems -- are not suited to the cloud, says Reichenberg. "I don't see the basic firewall management moving to the cloud any time soon," he says.

On the other hand, companies can outsource those functions to managed security services and improve their company's security posture, says Ben Feinstein, director of operations and development for the counter threat unit at managed security service provider Dell Secureworks.

"Most organizations still have a traditional set of network security controls that need to be managed and monitored, and a cloud service provider is not going to be able to do that," he says.

Managed security services offer a variety of levels of service, from threat intelligence that can help more technical security teams be more aware of the threats targeting their network, to more full-service offerings that can help nontechnical companies lock down their networks.

"Managed security service providers have a core competency and expertise around information security -- that is what they do, and they are experts," Feinstein says. "Also, they have global visibility across a number of different kinds of organizations, which allows them to have a better understanding of the threat landscape."

Have a comment on this story? Please click "Add Your Comment" below. If you'd like to contact Dark Reading's editors directly, send us a message.