American Bank Systems hit by ransomware attack, full 53 GB data dump leaked - Security Report. American Bank Systems (ABS), a service provider to US banks and financial institutions has suffered a ransomware attack with some of its clients’ data leaked. American Bank Systems (ABS), a company that provides services to U.S. financial institutions and banks helping them “operate efficiently and confidently in a rapidly evolving – highly regulated – environment” has been hit by a ransomware attack this month. Avaddon , the ransomware group behind the attack had earlier alleged they had acquired over 50 GB of the company’s proprietary data but had leaked a partial 4 GB dump earlier this month, part of which has been analyzed by Security Report News. Third-party company: ABS.