Ayodeji Kareem, 39, Babatunde Fafore, 41, and Vincent Alonge, 32, had tried to steal £4.25 million during the two-year fraud, reports Evening Standard of London.
The Nigerians hacked into thousands of bank accounts but were caught after a victim returned from holiday to find an email message containing 600 names, addresses and passwords.
This led the Police Central E-crime Unit to Alonge and then Kareem and Fafore via 4,000 emails between them and other gang members.
Kareem was found to have 2,660 credit and debit card numbers along with details of 1,552 accounts and 15 bogus bank web pages.
The gang used the bogus pages to con victims into revealing confidential information, which they then used to obtain credit cards.
Fafore, the “principle conspirator”, had the numbers for 490 cards, details of 1,982 bank accounts and three fake bank web pages. Alonge had 12,745 sets of card details, 182 sets of account details and 22 bogus web pages.
One victim was fleeced out of £219,000 after the gang obtained his signature from Companies House.
Fafore was jailed for five years and seven months, Kareem for five years and five months and Alonge for two years.