Ransomware

Spec sheet // Glossary // RANSOMWARE
Glossary / R / Ransomware
Glossary · GRC and resilience

Ransomware

Also called cyber extortion, ransom malware

Definition

Ransomware is malicious software that encrypts or steals an organisation's data and demands a payment, usually in cryptoassets, to restore access or stop publication. For financial firms it is an operational resilience, sanctions and reporting issue: paying can breach sanctions, and many regulators require notice of attacks and of any payment.

BACKUPSSEGMENTATIONMFA
Fig. 1 · Ransomware
OFAC ransomware advisory · NYDFS Part 500.17 · DORA Article 19
Key rulesOFAC ransomware advisory · NYDFS Part 500.17 · DORA Article 19 · UK ransomware proposals
Applies toVictims, financial institutions, insurers and incident response firms
RegionsGlobal · UK · EU · US
01

How it works

Attackers usually get in through phishing, stolen credentials or unpatched systems, then move across the network, copy data and encrypt systems. Many groups use double extortion, threatening to publish stolen data if the victim does not pay. Some operate as ransomware-as-a-service, renting their tools to affiliates. Firms defend with patching, multi-factor authentication, network segmentation, monitoring and offline backups that let them restore without paying.

When an attack happens, the firm activates its incident response plan, contains the damage, restores critical services and assesses what data was taken. Any decision to pay needs sanctions screening of the attackers and wallets, because a payment to a sanctioned person is a violation even if made unknowingly. Firms notify regulators within set deadlines, report to law enforcement and, where personal data is affected, notify data protection authorities and customers.

Step 1PreventPatch systems, enforce multi-factor authentication and keep offline backups.
Step 2DetectMonitor for intrusion, data theft and mass encryption.
Step 3ContainIsolate affected systems and activate the incident response plan.
Step 4ReportNotify regulators, law enforcement and affected customers on time.
Step 5RecoverRestore services from clean backups and screen any payment for sanctions.
02

The rules

US · 21 September 2021OFAC ransomware advisoryUpdated Advisory on Potential Sanctions Risks for Facilitating Ransomware Payments

OFAC strongly discourages ransom payments, warns that sanctions violations carry strict liability, and treats prompt reporting to law enforcement and cooperation as significant mitigating factors.

Victims, financial institutions, insurers and incident response firms
US · 1 December 2023NYDFS Part 500.1723 NYCRR 500.17 Notices to Superintendent, as amended by the Second Amendment to Part 500

Requires notice of cybersecurity incidents within 72 hours, notice of any extortion payment within 24 hours, and a written explanation of why payment was needed, alternatives and sanctions diligence within 30 days.

Banks, insurers and other entities licensed by the New York Department of Financial Services
EU · 17 January 2025DORA Article 19Regulation (EU) 2022/2554, Article 19, and Delegated Regulation (EU) 2025/301

Major ICT incidents, including ransomware attacks that meet the thresholds, need an initial notice within 4 hours of classification, an intermediate report within 72 hours and a final report within one month.

EU financial entities
UK · 22 July 2025UK ransomware proposalsRansomware: proposals to increase incident reporting and reduce payments to criminals, government response

The government confirmed plans for a targeted ban on ransom payments by public bodies and critical national infrastructure, a payment prevention regime and mandatory incident reporting; legislation is not yet in force.

Public sector bodies, critical national infrastructure operators and other UK organisations
03

Common questions

Is it illegal to pay a ransom?

Paying is not banned outright in the US, EU or UK for most firms, but a payment to a sanctioned person or country is a sanctions violation. The UK plans a ban for public bodies and critical national infrastructure operators.

Who must be told about a ransomware attack?

Depending on the firm, notice may go to the financial regulator, the data protection authority, law enforcement and affected customers. New York's DFS also requires notice within 24 hours of any extortion payment.

Does cyber insurance cover ransom payments?

Some policies cover extortion payments and recovery costs, subject to terms and exclusions. Insurers and their advisers still have to screen payments for sanctions, and OFAC's advisory applies to them as facilitators.