If your Microsoft 365 email account is compromised, it means someone unauthorised has gained access to your business emails. This can lead to sensitive information being exposed, emails being sent on your behalf, or even your entire email system being disrupted. For a small or medium-sized UK business, this situation can quickly escalate from a technical issue to a serious business risk.
Why this matters for UK SMEs
Email is often the backbone of daily communication and record-keeping. If hackers access your Microsoft 365 email, they might steal customer data, financial details, or confidential contracts. This can cause downtime as you try to regain control, reduce staff productivity, and damage your reputation with customers and suppliers. Additionally, under UK GDPR and the Data Protection Act 2018, a data breach involving personal information must be reported to the Information Commissioner's Office (ICO) within 72 hours, adding compliance pressure.
A typical scenario and response
Imagine a UK business with 50 staff notices unusual email activity: customers report receiving strange requests, and some employees can't access their mailboxes. Their IT partner quickly investigates and finds that a phishing attack allowed a hacker to log in. The partner immediately resets credentials, enforces multi-factor authentication (MFA) across all accounts, and checks email forwarding rules to prevent data leaks. They also review audit logs to identify what information was accessed and advise the business on notifying affected parties and the ICO if necessary.
Practical checklist: What to do if Microsoft 365 email is hacked
- Ask your IT provider: How quickly can they detect and respond to suspicious login activity? Do they monitor audit logs and unusual email rules?
- Review your security setup: Is multi-factor authentication (MFA) enabled for all users? Are password policies enforced and updated regularly?
- Check access controls: Who has admin rights in Microsoft 365? Are these limited to essential personnel?
- Verify backups: Are your emails and data regularly backed up off Microsoft 365? Can you restore quickly if needed?
- Audit email rules: Look for any unauthorised forwarding or auto-reply rules that could leak information.
- Train staff: Are employees aware of phishing risks and how to spot suspicious emails?
- Plan incident response: Do you have a clear process to follow if a breach occurs, including communication and reporting steps?
Next steps for peace of mind
Dealing with a Microsoft 365 email hack requires prompt, informed action to limit damage and restore security. Working with a trusted managed IT provider can help you set up strong defences like MFA, regular monitoring, and backup strategies tailored to your business needs. They can also support you through incident response and compliance requirements. If you haven't reviewed your email security recently, now is a good time to speak with an IT advisor who understands the risks and practical steps for UK SMEs.