They're highly portable, inexpensive, very popular - and a potential security nightmare. Running against the trend of mobile computers featuring progressively larger processors, memory, storage, screens and price tags, ultraportable netbooks promise to streamline and simplify their users' lives. Easy to carry, capable of running only a handful of modest applications and affordably priced, netbooks have emerged over the past year or so to become one of the hottest mobile computing trends.

Pioneered by Taiwanese PC maker with its Eee PC netbook and now also available from vendors such as Dell, Hewlett-Packard and Fujitsu, ultraportables are designed to appeal to users who need portable systems with more power and functionality than a smart phone but don't want to lug a conventional laptop through offices, hotels and airports.

That small package comes with built-in compromises, however. Netbooks typically feature a processor that lags at least a generation or two behind the CPUs included in traditional laptops, a few gigabytes of solid-state memory and storage, a squeezed-down display and a cramped keyboard. But another characteristic of the new portable pipsqueaks is striking fear into the hearts of a growing number of IT managers: security weaknesses that are directly attributable to the machines' diminished technology.

"This is a threat that IT managers are just beginning to recognize," says Brian Wolfe, a security analyst at Lazarus Technologies.

Asus Eee PC netbook

Minimized hardware resources force netbooks - and their users - to cope with weakened system software. Most models ship with a stripped-down Linux operating system or, in some cases, Microsoft's previous-generation operating system, Windows XP. Newer and more capable operating systems, which also tend to have the latest internal security safeguards, demand processing and storage power that netbooks typically lack, Wolfe notes.

Netbooks' reduced resources also limit their ability to run add-on security software, such as data encryption and anti-malware tools. With processing power, internal memory and storage space all at a premium, it can be difficult - sometimes impossible - to squeeze security software onto an ultraportable. "As a result, the machines are often sent out into the world with little or no protection," Wolfe says.

Vendors' use of dated software can also make netbooks more susceptible to various malware. Earlier this year, for example, Brazilian security firm Rise Security released an alert that showed that old, unpatched Samba code found on the Eee PC allowed the machine to be subverted ("rooted") right out of the box. Such vulnerabilities allow hackers to remotely gain complete control over the systems.

Other key security features are often absent on netbooks. "Many, if not most, [ultraportables] are sold without Trusted Platform Modules because they are targeted at the consumer market," says Rob Enderle, an analyst at Enderle Group. "This means they either don't have encryption solutions or the solutions aren't that robust."

Enderle also notes that most netbooks aren't designed to be managed centrally and therefore can't have their solid-state drives remotely wiped clean of data in the event of loss or theft.