Titan Rain was the code name given by the U.S. government to a series of cyber espionage attacks launched in 2003 on U.S. defense contractors, including those at Lockheed Martin, Sandia National Laboratories, Redstone Arsenal and NASA. The attacks were claimed to be of Chinese origin, although the Chinese government denied any involvement.
What was new in the attacks that began to emerge at this time was the level of deception and the use of multiple attack vectors (channels of attack), which combined well-researched social engineering attacks on specific, targeted individuals with stealthy Trojan horse attacks using malware techniques that were calculated to bypass contemporary security countermeasures.
The sensitive nature of the incidents and targets encouraged a blanket of government secrecy, which was understandable but, with hindsight, unfortunate because it helped the perpetrators to broaden their attacks to steal data from a wider spectrum of enterprises, encompassing all major sectors of industry including aerospace, defense, energy, financial services, manufacturing, pharmaceutical, technology and others.