The investigation into who hacked the server is still ongoing. ''Mother Jones'' reported that the hacker was at least familiar with the climate-science debate to know enough to search through the hacked emails using keywords like "Mann," "hockey stick," and "Phil Jones" and to sort them accordingly. A source close to the CRU explains that the unit's security wasn't very tight—its server is separate from the rest of the university's. But some complexity was involved: once the hacker breached the server, he still would have had to find his way into the system administrator's account, a feat that could have required special software to access the password. Then, in order to remain anonymous when posting the emails online, he would have had to scan the internet for nonsecure servers to work from to cover his own IP address. The hacker also used servers in multiple countries, making it difficult to trace his whereabouts.
It also later became clear that CRU was not the only target. In the fall of 2009, unknown parties posing as network technicians attempted to break into the office of a climate scientist at the University of Victoria in British Columbia. There were also attempts to gain access to servers at the Canadian Centre for Climate Modelling and Analysis. According to a source within the institution, there were also unsuccessful attempts to breach the server at the National Center for Atmospheric Research in Colorado. A US diplomatic cable that [[WikiLeaks]] released in late 2010 also revealed "evidence of an attempt to gain unauthorized entry to computer systems" belonging to the State Department's climate bureau in 2009. The cable warned that "as negotiations on the subject of climate change continue, it is probable intrusion attempts such as this will persist."<ref>Kate Sheppard, [http://motherjones.com/environment/2011/04/history-of-climategate "Climategate: What Really Happened?"] Mother Jones, April 21, 2011.</ref>
==Doubt as a tactic of [[climate skeptics]]==