TAIPEI Taiwan said on Tuesday several domestic securities and futures firms had experienced cyber attacks and at least 10 had been threatened with attacks if they did not pay blackmailers.
Investigators are looking into emails received by the brokerages seeking payment to avert cyber attacks known as distributed denial of service (DDoS).
Such attacks are among the most common on the internet.
They overload a website until it is forced to inhibit access or go offline. It has become a common tool for cyber criminals trying to cripple businesses and organizations with online activity.
"Since the beginning of February to today, 10 securities and futures brokerages have received blackmail emails with the home page website and electronic ordering system of some of them being attacked," the cabinet's cyber security department said in a statement.
Disruption to service and operation has lasted from 10 minutes to nearly four hours, it said.
The cyber threats and DDoS attacks had not impacted the operations of the brokerages, nor investors' rights because trading orders can be conducted via non-website methods such as telephone, fax or mobile phone apps, the department said.
It said the email threatened DDoS attacks on a brokerage's website if it did not pay 10 web-based digital currency bitcoins, or the equivalent to about T$300,000 ($9,650).
The cabinet said it would closely monitor the developments and coordinate across agencies "to raise protection levels and assist the Financial Supervisory Commission to stabilize financial order".
On Monday, the Financial Supervisory Commission, the island's financial regulator, said five brokerages reported they had been targeted.
Taiwan's top investigation agency said it was looking into the emails that were sent under the name of the Armada Collective, a hacking extortion group that has been linked to financial blackmail elsewhere.
The companies affected were mainly smaller domestic brokerages, including KGI Securities, Masterlink Securities Corp and its futures brokerage, Capital Securities Corp and its futures brokerage, and the securities arm of Cathay Financial Holding Co, according to the cabinet.
($1 = 31.0690 Taiwan dollars)
(Reporting by J.R. Wu; Editing by Robert Birsel)