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The top five internal security threats

• Tags:
• Policies,
• Risks,
• Workers,
• Block

Sally Whittle ZDNet.co.uk

Published: 10 Mar 2008 15:48 GMT

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...against new threats as they emerge, advises Paul Vlissidis, a technical director with NCC Group. "Don't rely on monthly or quarterly security downloads," he says. "The time between vulnerabilities being discovered and then exploited is shrinking all the time, so it's important to update patches and antivirus software regularly, and ideally layer several antivirus products rather than using just one."

In addition, consider whether your antivirus software can filter, monitor and block video content: few products can do this today, but a video of someone falling over can provide a cover for downloading all sorts of content onto the network, says Bob Tarzey, a service director with analyst firm Quocirca.

4. Information leakage
There are now a staggering number of ways that information can be taken from your computer networks and released outside the organisation. Whether it's an MP3 player, a CD-ROM, a digital camera or USB data stick, today's employees could easily take a significant chunk of your customer database out of the door in their back pocket.

"These types of devices are effectively very portable, very high-capacity hard drives," says Andy Kellett, a senior research analyst with Butler Group. "Someone can walk away with up to 60GB of data on a USB stick, so it's not a trivial matter."

Research conducted by Websense found that a quarter of UK workers who use PCs at work admit copying data onto mobile devices at least once a week. In addition, 40 percent say they use USB sticks to move data around, and a fifth have revealed their passwords to third parties.

Kellett advises companies to use software to specify policies on what devices can be connected to the corporate network, and what data can be downloaded. This should be enforced by the company — but workers should also be educated about why the policies are in place — or they will simply find a way to work around them. "It's not difficult to specify that the USB ports on desktop computers are disabled, or that CD-ROM drives are removed from computers where they aren't needed," Kellet says. "But you have to work with your employees to balance security and usability."

In addition, Kellett recommends considering whether to block access to web-based email and data-storage services, such as Gmail. "If someone can store confidential documents to an online storage site, that information is completely beyond your control," he says.

Finally, consider locking down networks to prevent wireless access using Bluetooth or Wi-Fi — except for authorised users with authorised devices. "Information loss over Bluetooth on an unsecured network is very difficult to detect indeed," says Kellett.

5. Illegal activities
It's important to remember that, as an employer, you are responsible for pretty much anything your employees do using your computer network — unless you can show you have taken reasonable steps to prevent this. Famously, the US-based Citibank was sued for $2m (£1m) when employees downloaded pornography from the internet, and UK companies have dismissed workers for a range of misdeeds, from selling drugs using company email to distributing racially and sexually offensive material over corporate intranets.

To protect yourself, experts advice a two-pronged approach. First, use monitoring software to check email and internet traffic for certain keywords or file types. You might also choose to block certain websites and applications completely.

Second, devise an Acceptable Use Policy spelling out employees' responsibility for network security, ensure it's signed by everyone and  that workers fully understand the risks and their responsibilities. According to software company Websense, one in five UK workers say they don't really understand their company's security policy.

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