IT departments go through all kinds of headaches to lock down their computers, only to have their employees undermine everything with foolish behavior out of the office. That's the conclusion of a new report by antivirus vendor Trend Micro.

The more mobile an end user is, the more likely he is to send confidential information via instant messaging or Web mail, the report found. These are points of weakness that even the most locked down of laptops can't block. They also engage in risky online behavior such as visiting social networks or downloading movies.

In the U.S., 58 percent of respondents with access to the Internet outside the company network admitted to sending confidential information by webmail, such as Google's Gmail or Yahoo Mail.

The risky business approach isn't limited to the U.S., either. Trend Micro found similar behavior in Europe and Japan, as well. Respondents from Germany, the U.K. and the U.S. all admitted to downloading files and movies and visiting social networks while on the company network.

In Japan, desktop workers were worse; 60 percent admitted to downloading executable files, compared with only 49 percent of mobile end users.

Trend Micro found that mobile users are often more technically savvy and better educated regarding security threats. For example, 61 percent of mobile end users in the U.S. are aware of Web threats like phishing (define), compared to 49 percent of desktop computer users.

The study "indicates just how important those mediums [IM and webmail] have become for business communication and that simply blocking access to those communication channels is no longer a feasible option for many corporations," said Dmitri Alperovitch, principal research scientist for Secure Computing, in a statement to Internetnews.com.

He was a little bothered by the fact that even though mobile users are more aware of Web threats than desktop users, they are still more likely to download executable files while on a company network. "This shows that security education is still lacking in many countries and for as long as that is the case, security technologies will remain the first and last line of defense," he said.

Natalie Lambert, senior analyst for client security at Forrester Research, wasn't surprised at the results. "I sat next to a guy on an airplane today who was complaining that his IT department prevents him from going to 'smut' sites. He was upset about it!" she told internetnews.com.

On a more serious note, she added: "Unfortunately, we are not seeing enough companies increasing the security protections on their mobile users. There are still many companies that only deploy AV to all machines. I spend much of my time talking to organizations about the multi-layered protections they need on their laptops, not just their network."