Cox Communications employee William Bryant recently pleaded guilty to information technology sabotage, having caused the loss of computer, telecommunications and emergency 911 services for thousands of Cox's business and residential customers throughout Dallas, Las Vegas, New Orleans and Baton Rouge . Bryant faces a 10-year jail sentence and a US$250,000 fine, but the future is less certain for Cox. Although services were fully restored, the incident's effect on Cox's reputation has yet to be determined.

The Cox story, along with recently publicized incidents at NASA, Accenture, Gap and Medco, serve as a harsh reminder that insiders represent a common and often misunderstood threat. Data theft and sabotage can result in hard costs, compliance-related problems, legal fees, productivity loss and, possibly most costly, loss of reputation.

Insider threats are up 17 per cent, according to the latest Computer Security Institute survey (a trend echoed by recent surveys by Deloitte and by CSO magazine). As IT and communication systems grow in complexity, so too do the numbers of employees, contractors and managed service providers required to maintain them. The spike in threats is not surprising given the often unfettered and unmonitored access these insiders have to critical corporate networks.

It should be clear that companies need to monitor insiders as aggressively as they do outsiders. However, policing insiders can prove challenging given the privileged access they require to do their jobs. Here are the five most common methods insiders use to access network resources and simple measures enterprise IT can take to protect against the implied threats.

1. Modems

A lack of central management combined with easy-to-guess static passwords make modems an ideal entry point for insiders with detailed knowledge of a network. Many companies have tried to address this challenge by simply unplugging modems until needed. However, unplugging modems makes it impossible to use them for their intended purpose, namely remotely restoring critical systems in times of emergency or outage.

Given that modems are a necessity, enterprises must extend the same security and identity confirmation measures to modems that they do to other remote-network entry points. Extending corporate two-factor authentication measures to modems or replacing legacy modems with newer, more secure models with embedded multifactor authentication can provide appropriate and cost-effective protection.

2. Open file transfer

Most organizations use open file transfer to patch network infrastructure. Internal technicians and vendors use this poorly secured, unrestricted access to troubleshoot, apply appropriate fixes and correct problems. However, they also can misuse this freedom to change files, remove critical components or disrupt systems, resulting in nonoperational systems, Web site defacements, data theft and other damaging situations.

A disgruntled or former employee could have the knowledge and motivation to commit such acts. However, more often, an insider threat can be less dramatic but equally troublesome. Even well-intentioned employees can be careless or make inadvertent mistakes. As such, protecting information assets requires you to have control over who can upload and download files, and a clear and easily retrievable record of all changes made to the system and the person who made them.

Traditionally, limiting and monitoring open file transfer required that individual permissions be set on each machine, causing headaches for IT departments. However, new technologies, such as vendor access and control (VAC) systems, can limit access and monitor activities organizationwide or for specific systems.