Email is still the number one entry point for cyber attacks. Not ransomware. Not zero-day exploits. Email.
This email security guide explains how modern email attacks actually work, why basic protections fail, and what Australian businesses should be doing in 2026 to protect their staff, data, and customers.
If your business uses Microsoft 365 or Google Workspace, email security is no longer optional. It’s a core business risk.
Why Email Is Still the Biggest Cybersecurity Risk
Most breaches don’t start with “hacking.” They start with someone opening a message that looks legitimate.
Attackers now use:
- AI-written phishing emails
- Perfectly cloned login pages and invoices
- Compromised real supplier accounts
- Fake internal requests from “the boss”
According to the Australian Cyber Security Centre, email remains the most common delivery method for malware and credential theft, which is why organisations are expected to implement layered email security controls.
The Real Cost of Poor Email Security
Weak email security leads to:
- Business Email Compromise (payment fraud)
- Account takeovers
- Data leaks
- Ransomware infections
- Compliance and legal exposure
- Reputation damage
And the worst part: most of these incidents are completely preventable.
How Modern Email Attacks Actually Work
Modern attacks don’t look suspicious.
They look like:
- A Microsoft login request from a real-looking sender
- A “shared document” link
- A supplier invoice that matches previous emails
- A message that appears to come from your own staff
Once one mailbox is compromised, attackers:
- Read real conversations
- Learn your workflows
- Send extremely convincing internal or supplier fraud emails
This is why basic spam filtering is no longer enough.
What Real Email Security Looks Like in 2026
Here is the reality most businesses need to understand:
Email Security Maturity Comparison
Security Area | Basic Setup (Unsafe) | Proper Modern Setup |
Domain Protection | No DMARC, partial SPF | SPF, DKIM, DMARC enforced |
Threat Detection | Simple spam filter | Advanced Threat Protection with link & attachment scanning |
Account Protection | Password only | MFA is enforced for all users |
Data Protection | No controls | DLP + automatic encryption |
Monitoring | No visibility | Continuous security monitoring & alerts |
If your setup looks more like the left column, you are exposed.
The 5 Critical Layers of Email Security
1) Domain Protection: SPF, DKIM, DMARC
These stop criminals from impersonating your company.
- SPF defines who can send email for your domain
- DKIM cryptographically signs your emails
- DMARC tells receiving servers what to do if something looks fake
Without DMARC, attackers can spoof your domain and attack your customers and staff.
Google and Microsoft both strongly recommend DMARC enforcement.
2) Advanced Threat Protection (Not Just Spam Filtering)
Modern systems scan:
- Links in real time
- Attachments in sandbox environments
- Sender behaviour and anomalies
This is how modern platforms stop:
- Credential-harvesting pages
- Zero-day malware
- Invoice fraud
- Weaponised PDFs and HTML files
3) Multi-Factor Authentication (MFA)
MFA blocks over 99% of account takeover attacks, according to Microsoft’s own security research.
If an attacker can’t log in, the attack usually dies immediately.
MFA should be:
- Mandatory for admins
- Mandatory for all users
- Enforced with conditional access policies
4) Data Loss Prevention & Encryption
Email is one of the easiest ways for data to leak.
Modern environments should:
- Detect sensitive information
- Block or encrypt those messages
- Prevent accidental or malicious data exfiltration
This protects:
- Client data
- Financial information
- Contracts
- Identity documents
5) The Human Layer: Training & Awareness
Technology alone is never enough.
Staff must:
- Recognise suspicious emails
- Verify unusual requests
- Report phishing instead of ignoring it
Companies that run regular phishing training and simulations suffer far fewer breaches over time.
Why Most Businesses Think They’re Safe (But Aren’t)
Many assume:
“We’re on Microsoft 365, so Microsoft handles security.”
In reality:
- Microsoft provides tools
- You must configure them properly
- Most tenants are dangerously under-secured
This is why businesses work with providers offering professional email security services:
And why many move to fully managed cyber security services with monitoring and response.
A Realistic Security Model for SMEs
A sensible setup includes:
- Proper SPF, DKIM, DMARC configuration
- Advanced Threat Protection
- MFA for every user
- Conditional access policies
- Ongoing monitoring
- Staff awareness training
This is no longer “enterprise-grade.” This is baseline business protection.
Important Limitations to Understand
No system is perfect.
- Some phishing will still get through
- Some people will still click
- Some attacks will still be new
That’s why detection, response, and containment matter just as much as prevention.
Security is a process, not a product.
What To Do Next
If you’re not 100% confident in your setup:
- Review your domain authentication
- Check MFA enforcement
- Audit your threat protection policies
- Assess your monitoring and response capability
This is exactly the type of work a managed IT and security partner like CodeHyper handles for Australian businesses.
FAQs
Is Microsoft 365 or Google Workspace secure by default?
No. They provide tools, but most environments are under-configured.
Is DMARC really necessary?
Yes. Without it, attackers can impersonate your domain.
Can small businesses be targeted?
They are targeted more often because they usually have weaker defences.
Does antivirus stop email attacks?
No. Most modern attacks use links and social engineering, not classic malware files.
