About 140 foreign intelligence organizations are trying to <A HREF="http://www.cnn.com/2007/US/10/19/cyber.threats/index.html">hack into the computer networks of the U.S. government</A> and U.S. companies, a top counterintelligence official said. Joel Brenner, the national counterintelligence executive, told CNN it is not accurate to blame only the Chinese government for recent penetrations of government computer systems. Because it's easy for hackers to disguise where an attack originates, Brenner said, the best course of action is to tighten up one's own networks rather than to place blame.