FOI reference: FOI-2025-2521
You asked
Please state how many malicious e-mails that were sent to you were blocked by your systems in (a) 2022, (b) 2023 and (c) 2024?
Please state how may Distributed Denial of Service (DDoS) attempts were made against websites run by your organisation that were blocked or repelled by your systems in (a) 2022, (b) 2023 and (c) 2024?
We said
The Office for National Statistics (ONS) records and logs are only be retained for as long as they are required, or according to system retention policies, and in line with current policy and legislation.
As such the logs relating to the number of malicious emails received and blocked are only retained for 90 days. During the last 90 days 485,908 emails have been blocked as malicious.
Logs relating to attempting Distributed Denial of Service (DDoS) attacks against the ONS website are only retained for 12 months.
In that previous 12 months there have been 15 attempted DDoS attacks in 2024 and 1 attempted DDoS attack in 2025.