The first 24 hours after a ransomware attack

← Security

Disconnect the affected systems from the network, but do not switch them off. Do not pay straight away, preserve evidence, and check the backup before restoring anything: if it was encrypted or infected too, restoring makes things worse. Report the incident, even while you do not yet know everything.

Updated on 28 August 2026

The first hour

Isolate, do not power off
Pull the network cable and turn off wifi. Powering down wipes memory, and that sometimes holds keys and traces needed later.
Establish how far it reaches
Which systems, which drives, which backup locations? Network shares and connected cloud folders are often caught as well.
Do not change passwords from an infected system
Do that from a device you know is clean.
Record what you see
Photos of the message, timestamps, file names. This is needed later for the report and the investigation.

The first day

Check the backup before restoring
Was the backup online or disconnected? Restoring from an infected backup simply brings the problem back.
Report the incident
Where personal data is involved, there is a duty to notify the supervisory authority, in principle within 72 hours. Reporting to the police is possible alongside that.
Tell the people it affects
Customers, suppliers and staff would rather hear it from you than from someone else.
Paying is a last resort
Payment offers no guarantee, funds the next attack and can be legally problematic. Discuss it only once every other route is closed.

Afterwards

Rebuild clean
Cleaning an infected system is less reliable than reinstalling from a clean base.
Find out how they got in
Without that answer the same door stands open again next month.
Revisit access
Multi-factor authentication, fewer rights per account, and a backup that cannot be reached from the network.

We help limit the damage, restore safely and close the route it came in through. That last part is what stops it happening again six months from now.

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