Many Asian organisations are badly defended against cyber-attacks, a year-long investigation by US security company Mandiant indicates.
The median time between a breach and its discovery was 520 days, it says. That is three times the global average.
Asia was also 80% more likely to be targeted by hackers than other parts of the world, the report said.
It said an average of 3.7GB in data had been stolen in each attack, which could be tens of thousands of documents.
However, the bulk of the incidents were not made public because the region lacks breach disclosure laws.