Almost a year after students ended pro-democracy street protests in Hong Kong, they face an online battle against what Western security experts say are China-sponsored hackers using techniques rarely seen elsewhere.
Hackers have expanded their attacks to parking malware on popular file-sharing services including Dropbox and Google Drive to trap victims into downloading infected files and compromising sensitive information. They also use more sophisticated tactics, honing in on specific targets through so-called 'white lists' that only infect certain visitors to compromised websites.
Security experts say such techniques are only used by sophisticated hackers from China and Russia, usually for surveillance and information extraction.
The level of hacking is a sign, they say, of how important China views Hong Kong, where 79 days of protests late last year brought parts of the territory, a major regional financial hub, to a standstill. The scale of the protests raised concerns in Beijing about political unrest on China's periphery.
"We're the most co-ordinated opposition group on Chinese soil, (and) have a reasonable assumption that Beijing is behind the hacking," said Lam Cheuk-ting, chief executive of Hong Kong's Democratic Party, which says it has been a victim of cyber attacks on its website and some members' email accounts.