According to this World Tribune article Chinese hackers are believed have left “trap doors” in Pentagon computers after a series of attacks on government email servers. The “trap doors” allow others to access those systems after a hacker has broken the security and officials think these hacks were designed to allow the Chinese to shut down or disrupt military or intelligence systems during a time of war.

Germany complained to President Hu Jintao of Chinese incursions into government systems recently, fanning fears of a coming Chinese cyber attack on Western infrastructure similar to the Estonia attack that virtually shut down that country. Britain, France Japan and South Korea have all complained of Chinese attacks on their systems.

From World Tribune:

U.S. intelligence officials disclosed that one objective of the Chinese hacking is to plant “trap doors” into government computer systems that would permit shutting down or disrupting the systems in war time. Some government agencies were forced to spend tens of thousands of dollars replacing compromised computers because they could not be certain that Chinese hackers had not left hidden access points in them.

Wolfsaid last week that four computers in his congressional office had been compromised by hackers from China in August 2006. Other members also were attacked, along with members who traveled abroad using portable computers, he said.

“In subsequent meetings with House Information Resources and officials from the FBI, I was told not only that other members and at least one committee of the House had been similarly compromised, but that the outside sources responsible for this attack came from within the People’s Republic of China,” Wolf said in a statement on the House floor.

As early as 2001 Wired ran an article accusing the Chinese of the same thing. That article also claimed U.S. based hackers were “retaliating” against Chinese systems.

h/t N.T.A.