What does it mean if your email has been hacked?

An email account is considered “hacked” when an unauthorised party gains access and can read, send, delete, or manipulate messages. This often happens after a phishing attack, password reuse, or compromised credentials.

Because email is the gateway to many other systems, a hacked inbox can quickly lead to:

• Data theft

• Invoice and payment fraud

• Internal phishing

• Wider account compromise across cloud services

Common signs your email has been compromised

You may notice:

• Emails sent that you didn’t write

• Password reset notifications you didn’t request

• Missing or deleted emails

• New mailbox rules or auto-forwarding

• Login alerts from unfamiliar locations

• Contacts reporting suspicious messages from you

Even subtle signs should be taken seriously.

Immediate actions (first 15 minutes)

1. Change the email password immediately Use a strong, unique password that isn’t used anywhere else.

2. Revoke active sessions Force sign-out across all devices to remove attacker access.

3. Enable or confirm MFA Check that MFA is active and review registered methods (apps, phone numbers).

4. Preserve evidence Save examples of suspicious emails, login alerts, and rule changes.Note the time the issue was first noticed.

Check for silent persistence (critical step)

Attackers often try to maintain access even after a password reset.

Check for:

• Mailbox rules that auto-delete or forward emails

• Email forwarding to external addresses

• OAuth / third-party app access you don’t recognise

• Recovery email or phone number changes

• Admin role changes (for business accounts)

This step is frequently missed — and it’s how attackers regain access later.

Assess what else may be affected

A hacked email account is often used to pivot into other systems.

Review:

• Cloud storage (OneDrive, SharePoint)

• CRM and finance platforms

• Password reset activity for other services

• Internal systems that rely on email for authentication

• Recent invoices, payment details, or supplier communications

If email was used for password resets elsewhere, those accounts should be treated as compromised too.

What NOT to do

• Don’t assume it’s fixed after changing the password.

• Don’t ignore forwarding rules or app permissions.

• Don’t delay internal communication. Silence increases risk to others.

Containment and remediation

Once immediate access is removed:

• Reset passwords for any linked or reused credentials

• Remove unauthorised rules, forwarding, and app access

• Review MFA and conditional access policies

• Monitor login activity closely for several days

• Scan endpoints used by the affected user

Do you need to tell anyone?

You may need to notify:

• Internal teams if internal phishing was sent

• Clients or suppliers if they may receive fraudulent messages

• Compliance/legal teams if sensitive or personal data was accessed

Whether external reporting is required depends on the data involved and confirmed exposure.

Preventing future email compromises

Most email hacks exploit:

• Weak or reused passwords

• Missing MFA

• Poor visibility into account activity

Key preventative measures include:

• MFA for all email accounts

• Conditional access policies

• Regular mailbox and sign-in reviews

• User awareness around phishing

• Monitoring for suspicious rules and app access

Signs the attacker may still have access

After remediation, watch for:

• Rules or forwarding reappearing

• Repeated MFA prompts

• Unexpected password resets

• Login attempts from unfamiliar locations

• Continued reports of suspicious emails

Any of these should be treated as an active incident.

People Also Ask

How serious is a hacked email account?

Very. Email is often the entry point to other systems and can be used for fraud, data theft, and internal phishing.

Can attackers still access my email after I change the password?

Yes — if mailbox rules, OAuth apps, or recovery details aren’t checked and removed.

Should I tell clients if my email was hacked?

If there’s a risk they may receive fraudulent messages, it’s usually better to warn them early.

Can email hacks lead to ransomware?

Yes. Compromised email accounts are commonly used to distribute malware or gain access to wider systems.

How long should monitoring continue after an email hack?

At least several days to a few weeks, depending on severity and what access the attacker had.