The National Cyber Security Centre is now working with firms across the country to establish the full extent of the hacks on Microsoft Exchange servers.
NCSC director for operations, Paul Chichester, explained that the organisation is working closely with industry and international partners to understand the scale and impact of UK exposure.
Chichester added: “It is vital that all organisations take immediate steps to protect their networks. Whilst this work is ongoing, the most important action is to install the latest Microsoft updates.”
The NCSC encouraged all organisations to install the latest Microsoft Exchange server updates “as a matter of urgency.”
Last week, Microsoft warned of a large-scale exploitation of vulnerabilities. Cyber-security firm Eset identified more than 5,000 email servers around the world that have been affected by the incident, many of which are in the UK.