The term has been used for some time in government and military domains to describe targeted cyberattacks carried out by highly organized state-sponsored groups with deep technical skills and computing resources.

Such attacks are typically highly targeted, stealthy, customized and persistent. They also often involve intensive surveillance and advanced social engineering. In many cases, the attacks target highly placed individuals within organizations who are tricked into visiting malicious sites or downloading malicious software onto their systems. The goal in most of these attacks is to steal trade secrets rather than personal or financial data.

Government networks, especially those of the Department of Defense, have been the target of such advanced persistent threats for years. But as the attacks against Google and others show, these threats are spilling over into the commercial side.

Writing in a blog post Thursday, security vendor McAfee's chief technology officer George Kurtz noted that APTs had begun to change the threat landscape.

"These attacks have demonstrated that companies of all sectors are very lucrative targets," Kurtz said. APTs, he noted, have become "the equivalent of the modern drone on the battlefield. With pinpoint accuracy they deliver their deadly payload and once discovered - it is too late."

Confronting the threat does not always require the implementation of new technologies. But it does require rethinking some of the strategies that companies may be adopting to protecting data, Kurtz and others said. Among the steps:

1. Your adversaries are not just organized crime any more

Given the enormous growth in organized cybercrime over the past few years, most companies have implemented defenses for protecting personal and financial data from theft. While that's important, it's also essential for companies to think about protecting their intellectual property data, said Ed Skoudis, co-founder of InGuardians, a Washington-based security consultancy.

"The threat has shifted," Skoudis said. "If you go back over 10 years, the primary threats we faced were from hobbyists. Then the landscape changed, and the primary threat we most had to deal with was organized crime. And now it has shifted again," he said.

Many cyberattackers are more are interested in corporate espionage and in stealing intellectual property than they are in going after credit card numbers or patient health data.

"There's still the concern about people stealing 27 million cards," Skoudis said. But a failure to adequately protect IP and corporate secrets against similar theft could result in far more long-term damage, he said. "You got to realize what your threat is and how to look for it," he said.

2. Add network monitoring to the task list

Advanced persistent threats by definition are designed to get around firewalls, antivirus software, intrusion detection systems and other controls a company might have in place for blocking illegal access to data. So companies need to have tools for monitoring anomalous behavior on their network, and for detecting unusual long-term persistent network connections and other "outlier behavior" Skoudis said.

Companies might also want to consider using more "white-listing" approaches to block all but a very narrow and specific set of "known good" activities on their systems and networks , Kurtz said speaking with Computerworld on Friday.

"A lot of infections and zero-day threats can be eliminated using white listing because only trusted code can run on the system," he said.

Also vital is the need for companies to monitor their logs closely, Skoudis said. Looking at firewall logs, network based IDS alerts and Web proxy server logs can help companies identify suspicious activity on their networks, he said.

Companies need to establish a baseline for normal behavior on their networks and then regularly compare log data against this baseline to detect malicious activity, he said.

"The APT tries to be the needle in the haystack. You need to go through the information you already are gathering to find it," he said. "You've got to be looking for those outliers," he said.

3. Most Web attacks still require human intervention to succeed

Targeted attacks depend on humans clicking on something or browsing over to a malicious Web site, Kurtz said. McAfee's analysis of the attacks against Google and other companies showed that intruders gained access to an organization by sending a tailored attack to one or a few targeted individuals.

The attacks were probably designed to look like they came from a trusted source, leading the target to click on a link or file.

"There's much more upfront reconnaissance taking place these days," with intruders lurking in social networking sites and elsewhere to gather information on targets, he said. Strong user authentication and access control measures can help mitigate this issue, Kurtz said.

Tools are also available that can help companies verify the authenticity of links that users might click on, to help prevent them from browsing to a malicious Web site or downloading malware, he said.

Lastly, companies need to continue emphasizing user education and training, he said. "A lot of these attacks involve a human element. There is no patch" against that.

**Jaikumar Vijayan covers data security and privacy issues, financial services security and e-voting for Computerworld. Follow Jaikumar on Twitter at Twitter@jaivijayan, send e-mail to jvijayan@computerworld.com or subscribe to Jaikumar's RSS feed Vijayan RSS.