Since at least 2005, APT30 distributed malicious software, known as malware, that then gave hackers access to computers among countries in the Association of Southeast Asian Nations and India, FireEye said in a report released on Monday.
China's foreign ministry, defence ministry and Internet regulator have repeatedly denied that the nation is behind any cyber attacks. Hua Chunying, a foreign ministry spokeswoman, told reporters on March 30 that the country is "one of the major victims" of cyber attacks.
China's Cyberspace Administration Office didn't immediately respond to faxed questions about the FireEye report.
According to University of Toronto researchers, China has begun using an "offensive system" able to disrupt access to websites outside its borders.
The deployment of this system represents a "significant escalation in state-level information control," the university's Citizen Lab said in a report posted to its website on Friday. This system, dubbed the "Great Cannon," was used in recent attacks on GitHub and servers used by GreatFire.org, according to the university's report.
APT30 used a package of software, named Backspace and Neteagle, and related tools called Shipshape, Spaceship and Flashflood, to go after files from targets involved in political, military, and economic affairs, according to the FireEye report. Media organisations and journalists were also targeted, it said.
Targeting of computers not directly connected to the Internet - known as air-gapped networks - showed the hackers were seeking the most-sensitive types of information and knew how to exploit USB thumb drives to steal files, Boland said. Its targeting of air-gapped systems since 2005 is one of the earliest observed examples of such a strategy, FireEye said.
"The attacks against the high-tech sector were quite focused on gaining access to schematics and design information for products," Boland said, declining to name specific targets.
By sending emails that appeared to come from legitimate correspondents, including letters written fluently in local languages such as Thai, the hackers were able to trick targets into opening infected documents that installed malware.
In one instance, hackers sent an email purporting to come from a trusted source - known as spear phishing - to more than 50 journalists with a subject line containing the phrase "China MFA Press Briefing," FireEye said. MFA is an abbreviation for the Ministry of Foreign Affairs.
FireEye identified seven countries as confirmed targets, including India and the US. A further 10 nations were classified as "likely" targets.
The APT30 group used spear phishing techniques to seek information on military relations between China and India and contested regions, FireEye said.
Orderly updates of the malware and the keeping of detailed records of software versions indicate a large, efficient and tightly run group, FireEye said.
"We have observed APT30 target national governments, regionally-based companies in 10 industries, and members of the media who report on regional affairs and Chinese government issues," FireEye said. "The group expresses a distinct interest in organisations and governments associated with ASEAN, particularly so around the time of official ASEAN meetings."
APT30 released customised variants of its malware to coincide with ASEAN meetings in Jakarta, Phnom Penh and New Delhi, according to the report.
- Bloomberg