Interviewed at his downtown Taipei office, Wu's set-up fits the classic hacker image: dimly-lit, strewn with wires and humming with computers.
On a projector screen he displayed a list of emails, written in Chinese, with subject headings like "meeting notes", "dinner attendance" and "questionnaire".
"These are all hacking attempts," Wu explained. Once the documents have been opened, they plant a backdoor allowing the hacker virtually unfettered access to the network.
One such "spearphishing" attack was reportedly used on the White House in October. A Taiwan expert in cyberespionage interviewed by Reuters estimated that thousands of Taiwanese high-level government employees receive as many as 20 to 30 of these emails a month.
"We've been following these Chinese hackers for so long, we can track their daily work schedule," said the expert, who asked not to be identified.
"People expect hackers to be night owls, but these guys work very normal hours - on Chinese national holidays, for example, we don't see any hacking activity at all."
Tracking the exact source of the attacks, however, remains a slippery game of internet sleuth.
"We take the IP address culled from the attack as a springboard, then track it through the internet - perhaps the same IP address was used in a forum registration, or to register a QQ handle," he said, referring to a popular Chinese chat program. "It depends how good they are at covering their tracks."
China denies being behind hacking attacks on other nations and insists it is a major victim of cyber attacks, including from the United States - an argument that Beijing sees as strengthened by revelations last month from a former National Security Agency contractor, Edward Snowden, about top-secret US electronic surveillance programs.
The United States and China held talks focused on cyber issues last week.
According to internet platform Akamai, 27 per cent of worldwide hacking activity during 2012 originated in China. The same report, however, also placed Taiwan among the top five digital attack originating countries in 2012.
"Taiwan is one of the key countries where we see a lot of activity," said Singapore-based malware researcher Chong Rong Hwa of network security firm FireEye.
A report issued by SecureWorks, a network safety arm of PC maker Dell, said Taiwan government ministries are swarming with a particularly malicious form of data-nabbing computer virus.
In one year, the Taiwan National Security Bureau encountered more than 3 million hacking attempts from China, according to statements given by bureau director Tsai Teh-sheng in March in response to questions from politicians.
Military and technology intelligence was included among the pilfered data. A representative from the bureau declined to comment when contacted by Reuters.
"Taiwan will continue to be the battleground for lots of cyber attacks; it's like we are on our own," Wu said. "China has a huge pool of talent and technical resources."
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