San Francisco, Oct 16 : Top 10 hacking groups have executed ransomware attacks worth a whopping $5.2 billion in Bitcoin over the past three years, according to a US treasury report. The report, released by the US Treasury's Financial Crimes Enforcement Network (FinCEN) on Friday, found that ransomware-related transactions totalled around $590 million from January 2021 to June 2021, exceeding the $416 million reported for entire 2020. "The FinCEN analysis of ransomware-related suspicious activity reports (SARs) filed during the first half of 2021 indicates that ransomware is an increasing threat to the US financial sector, businesses and the public," the report said. "The number of ransomware-related SARs filed monthly has grown rapidly, with 635 SARs filed and 458 transactions reported between January 1, 2021 and June 30, 2021, up 30 per cent from the total of 487 SARs filed for the entire 2020 calendar year," it added. The report analysed 177 unique convertible virtual currency wallet addresses used for ransomware-related payments associated with the 10 most commonly-reported ransomware variants in SARs during the review period, reports ZDNet. The report analysed the massive growth in ransomware payments in the first half of 2021 by looking at suspicious activity reports from financial institutions. FinCEN identified Bitcoin as the most common ransomware-related payment method in reported transactions. Bitcoin was trading at over $60,000 per coin on Saturday. FinCen found a total of 68 different ransomware variants. The report lists the most commonly reported variants, which are REvil/Sodinokibi, Conti, DarkSide, Avaddon and Phobos, among others. The report came after more than 30 countries, including South Korea, Japan and the UK, this week pledged to work together to combat the growing threat of ransomware attacks in a virtual conference hosted by the US. The White House-led meeting came after a series of recent ransomware attacks on US businesses that have crippled their systems by infiltrating them and locking them up until a ransom is paid. /IANS