Have I Been Hacked? 10 Warning Signs to Look Out For (…and what to do next)
Most people imagine being hacked as a dramatic event where their screen suddenly fills with warning messages and everything stops working.
The reality is often much quieter.
In many cases, cyber criminals can gain access to your accounts, devices or email systems without you realising immediately.
The sooner you spot the signs, the quicker you can limit the damage.
At SiSTEMZ, we regularly help both individuals and businesses investigate suspicious activity. Here are some common warning signs to look out for.
1. You are receiving password reset emails you didn't request
This is often one of the first indicators.
You may receive emails saying:
Your password has been changed
Someone has attempted to log in
A verification code has been requested
A new device has been added to your account
Never ignore these notifications.
Even if the login attempt was unsuccessful, someone may have obtained your email address and is trying to access your accounts.
2. Your contacts say they're receiving strange emails from you
This is one of the most common business issues we encounter.
People may tell you:
"Did you send me this link?"
"Have you shared a document with me?"
"Why are you asking me to buy gift cards?"
If you didn't send these messages, act immediately.
Cyber criminals often use compromised accounts to target colleagues, customers and suppliers.
3. Check your email filters and forwarding rules
This is one of the most overlooked areas.
Hackers frequently create hidden rules inside email accounts to avoid detection.
These rules can:
Automatically forward copies of your emails elsewhere
Delete security notifications
Move important emails into hidden folders
Redirect invoices or payment requests
In Microsoft Outlook or Microsoft 365 check:
Rules
Forwarding settings
Deleted Items
Junk Email
In Gmail check:
Filters and blocked addresses
Forwarding settings
Delegated account access
If you see anything you don't recognise, remove it immediately.
Sistemz Tip: We always recommend checking filters and forwarding rules as part of any suspected email compromise.
4. Your device suddenly becomes very slow
Whilst slow devices are not always a sign of hacking, unexplained changes can indicate something is running in the background.
Look out for:
Constant fan noise
Programs opening by themselves
Unexpected pop-ups
Very slow internet browsing
Significant battery drain
If the behaviour is unusual and appeared suddenly, it is worth investigating.
5. You notice unfamiliar logins
Many online accounts allow you to view recent activity.
Check for:
Unknown locations
New devices
Unusual login times
This is available on many services including:
Google
Apple
Microsoft
Facebook
LinkedIn
If you don't recognise a device, sign it out immediately.
6. Multi-Factor Authentication notifications keep appearing
Are you constantly receiving approval requests that you didn't initiate?
Never press "Approve" simply to make them disappear.
Repeated authentication requests may indicate someone already has your password and is trying to gain access.
This is sometimes called MFA fatigue.
Instead:
Reject the request
Change your password immediately
Review account activity
7. Unexpected purchases or financial transactions
Check:
Bank accounts
PayPal
Amazon
Apple subscriptions
Google subscriptions
Small transactions are sometimes used to test stolen payment information before larger purchases are attempted.
8. Your antivirus is disabled
Some malicious software attempts to disable your security protections.
Check that:
Antivirus is running
Real-time protection is enabled
Security updates are current
If your antivirus has been disabled without your knowledge, investigate further.
9. Files have gone missing or changed
Watch out for:
Documents renamed
Files disappearing
Unknown files appearing
Folders moving location
Always check your backups before making major changes.
10. Trust your instincts
People often tell us:
"Something just doesn't feel right."
That instinct is often correct.
If your technology is behaving differently, don't ignore it.
Small issues caught early are much easier to resolve.
What Should You Do If You Think You've Been Hacked?
Stay calm and work through these steps.
Immediate Action Checklist
1. Disconnect the device from the Internet
Temporarily disconnect Wi-Fi or unplug the network cable if you suspect active malicious activity.
2. Change your passwords
Prioritise:
Email accounts
Banking
Microsoft accounts
Google accounts
Apple accounts
Use strong, unique passwords for every account.
3. Enable Multi-Factor Authentication (MFA)
If it's not already enabled, turn it on.
4. Check email rules, filters and forwarding settings
This step is extremely important and often forgotten.
5. Run a security scan
Use reputable antivirus software to scan the device.
6. Inform relevant people
If a work account has been compromised, inform:
Colleagues
Customers
Suppliers
This can help prevent further attacks.
Prevention is better than cure
Keep devices updated
Use strong passwords
Enable multi-factor authentication
Back up your data regularly
Check email filters periodically
Be cautious with links and attachments
Don't reuse passwords across multiple accounts
Final thoughts…
Being hacked doesn't necessarily mean you have done something wrong.
Cyber criminals are becoming increasingly sophisticated and target both individuals and businesses every day.
The important thing is recognising the warning signs early and acting quickly.
At SiSTEMZ, we help customers identify suspicious activity, secure compromised accounts and put practical measures in place to reduce future risks.
Sometimes a simple health check can provide enormous peace of mind.
Think something isn't quite right? Get in touch with SiSTEMZ and we will help investigate before a small issue becomes a much bigger problem!
