A major US security company claimed on Wednesday that experts in the country have discovered the largest series of hacking activities to date that involve over 70 organizations, including the UN and the International Olympic Committee (IOC).
The California-based McAfee firm, which uncovered the intrusions, said in a report that it believed there was one "state actor" behind the attacks but declined to name it, though one American security expert said the evidence points to China.
However, Chinese analysts dismissed the US expert's allegation as "groundless" as McAfee's report is largely business-motivated and cannot be trusted.
Among other victims of the five-year attacks are the governments of the US, India and South Korea, according to a report published on McAfee's website.
McAfee dubbed the hackings "Operation Shady RAT" and said the earliest breaches date back to mid-2006, though there might have been other intrusions.
"What we have witnessed over the past five to six years has been nothing short of a historically unprecedented transfer of wealth," McAfee vice president for threat research Dmitri Alperovitch said.
"The credibility of the report issued by a business company over cyber security threats from other countries is definitely in doubt," Li Wei, a security expert with the China Institute of Contemporary International Relations, told the Global Times.
"McAfee undoubtedly raised its own reputation by issuing such a report and exaggerating threats from other countries, through which it hoped to gain more economic benefits," said Li Wei, noting that the company chose not to refer to the "state actor" by name.
"For McAfee, this is definitely the best choice to seek business gains while avoiding any accusations," he added.
The company said it had alerted victims of the attacks and had also informed law enforcement agencies that are investigating the intrusions.
However, Mark Adams, a spokesman for the IOC, told the NYT that they are "unaware" of the alleged intrusions claimed by McAfee.
Jim Lewis, a cyber expert with the Center for Strategic and International Studies, said to Reuters that it was very likely China was behind the campaign because some of the targets had information that would be of particular interest to Beijing.
"To level accusations at China based on McAfee is totally baseless considering that the US is the first country to create a cyber military command and top hackers attend the Black Hat conference in Las Vegas every year," Li said.
Agencies contributed to this story