Search giant Google has revealed that it is in the process of auditing its internal security, following the revelation that it not only had its systems hacked by external sources, likely to originate from China, but they may been aided from within.

The attacks and suspected corporate espionage have forced Google to consider pulling out of one of the world’s most lucrative markets.

The company indicates that it was hit by a ‘sophisticated’ attack to its network in mid-December 2009, but is in the process of locating and preventing future attacks.

It also found that the attacks were not just on Google itself.

“Like many other well-known organizations, we face cyber attacks of varying degrees on a regular basis. In mid-December, we detected a highly sophisticated and targeted attack on our corporate infrastructure originating from China that resulted in the theft of intellectual property from Google. However, it soon became clear that what at first appeared to be solely a security incident – albeit a significant one – was something quite different,” David Drummond, SVP corporate development and chief legal officer, posted on the company’s official blog.

“First, this attack was not just on Google. As part of our investigation we have discovered that at least 20 other large companies from a wide range of businesses… have been similarly targeted.”

Drummond goes on to explain that it has evidence that a primary goal of the attackers was accessing the Gmail accounts of Chinese human rights activists.