NotPetya ransomware attack in 2017, which collectively resulted in an estimated $10 billion in global financial impact across all of the affected entities.

Financial Market

Banks are at high risk because they hold the data and funds of private clients and they provide access to their services through multiple online and digital channels, Moody's writes.

"Securities firms, including capital markets firms, are also at high risk," the Moody's report notes. "They are appealing targets for cybercriminals aiming to carry out large-scale theft as well as sophisticated attacks designed to create operational disruption or garner publicity. A successful attack on large, systemic banks could pose a systemwide risk, reflecting their high degree of interconnectedness."

Similarly, successful cyberattacks against market infrastructure providers, such as exchanges and clearinghouses, or counterparties such as large securities orcapital markets firms, could impair the booking, clearing and settlement of financial transactions, the report says.

Healthcare Market

Moody's assesses three main subsectors in healthcare: hospitals, pharmaceutical companies and medical device manufacturers. "Each industry has somewhat different cyber risk profiles that reflect their relative vulnerability to an attack and the impact of a successful attack," Moody's notes.

"For hospitals, our assessment primarily reflects the sensitive and essential nature of the data collected and used by these entities and its attractiveness to hackers, as well as vulnerabilities emanating from increasingly connected medical devices."

Hospitals of all sizes are vulnerable to cyberattacks and the subsequent financial impact, the report notes. "Although hospitals with more financial resources will be better able to avoid threats or recover from an attack, size does not provide immunity."

Electronic medical