'World's largest botnet' taken down as alleged Chinese mastermind arrested and $29m in cryptocurrency seized

A Chinese national has been arrested for allegedly being the mastermind behind a huge botnet used to steal billions of dollars.

The "911 S5" botnet was likely the world's largest - and infected computers in nearly 200 countries and facilitated a whole host of crimes including financial frauds, identity theft and child exploitation, said FBI director Christopher Wray.

Yunhe Wang allegedly made at least $99m (£78m) - buying luxury cars and properties all over the world - by selling access to criminals who used it for scams.

A botnet is a network of infected computers that hackers operate remotely to conduct mass cyber attacks and scams.

The "zombie" machines are at their mercy and can be used to gather personal data, monitor activity and install applications.

Wang, 35, was arrested in Singapore last week and $29m (£22.8m) in cryptocurrency seized, said Brett Leatherman - the FBI's deputy assistant director for cyber operations.

The botnet was used to to steal "billions of dollars from financial institutions, credit card issuers and accountholders, and federal lending programs since 2014", according to an indictment filed in Texas.

The network allegedly included 613,000 infected machines in the US alone.

US Attorney General Merrick Garland said criminals using it committed about $5.9bn (£4.64bn) in fraud, including 560,000 bogus unemployment insurance claims.

Wang used his millions to buy 21 properties in the UAE, the US, China, Singapore, Thailand and St. Kitts and Nevis - where he obtained citizenship, said prosecutors.

Cars including a Rolls-Royce, two BMWs and a Ferrari - as well as luxury watches - are among assets that could be seized.

If convicted, Wang faces up to 65 years in jail over charges including computer fraud and money laundering.

Authorities from the US, Singapore, Thailand and Germany were involved in the operation to arrest him and disrupt the botnet, the FBI said.

Read more from Sky News:
'Bad breath rapist' found 17 years after crime
Billionaire to take two-person sub to depths of Titanic

"The conduct alleged here reads like it's ripped from a screenplay," said Matthew S. Axelrod, from the US Bureau of Industry and Security.

"A scheme to sell access to millions of malware-infected computers worldwide, enabling criminals over the world to steal billions of dollars, transmit bomb threats, and exchange child exploitation materials - then using the scheme's nearly $100m in profits to buy luxury cars, watches, and real estate."