Email Security for Australian Businesses: Stop Phishing and Business Email Compromise

One bad click can halt your business. This guide shows Brisbane teams how to lock down email security in a morning using Microsoft 365 and smart DNS controls. Stop phishing and business email compromise with simple steps any SME can follow.

Key takeaways

• Turn on multi‑factor authentication for every account. It blocks most account takeovers fast.
• Set Microsoft Defender anti‑phish, Safe Links, and Safe Attachments to recommended or strict.
• Publish SPF, turn on DKIM, and add DMARC with p=quarantine, then move to p=reject once email flows are clean.
• Run short staff training and monthly phishing simulations. It cuts risky clicks.
• Use a layered filter for spam and malware. See our email security and spam filtering tips.

Email security: what it is and core concept

Definition

Email security is the mix of settings, training, and checks that protect mailboxes and domains from phishing, malware, and payment fraud. It includes phishing protection in Microsoft 365, multi‑factor authentication, SPF, DKIM, and DMARC. The goal is simple: keep bad emails out and stop account misuse.

Why it matters

In Brisbane, most business breaches start with email. Scammers target invoice changes, supplier fraud, and Microsoft 365 logins. Busy teams in Fortitude Valley, Logan, and Ipswich run on email all day. A single click can stall jobs, slow cash flow, and trigger OAIC reporting. Strong basics reduce that risk fast.

How it works and step-by-step

Process

Use this fast sequence:

• Turn on multi‑factor authentication for all users, service accounts, and admins. Block legacy authentication.
• Apply Microsoft Defender for Office 365: enable anti‑phish, Safe Links, and Safe Attachments with recommended or strict policies.
• Publish SPF for your domain. Enable DKIM in Microsoft 365. Add a DMARC record with p=quarantine, then move to p=reject after review.
• Harden mailboxes: disable auto‑forward to external, alert on inbox rule creation, monitor sign‑ins by country.
• Set Conditional Access: require MFA, block risky locations, and protect admin roles.
• Train staff. Run monthly phishing simulations and quick refreshers.
• Monitor: check Secure Score weekly and message trace for suspicious sends. Review DMARC reports.
• Prepare an incident plan: who to call, how to reset, and how to warn clients if needed.

Featured answer

To stop phishing in Microsoft 365, require multi‑factor authentication, disable legacy authentication, and apply Defender anti‑phish, Safe Links, and Safe Attachments. Publish SPF, enable DKIM, and set DMARC to quarantine, then reject. Train staff monthly and alert on inbox rules, external forwarding, and unusual sign‑ins.

Essential protections: MFA, anti‑phish, Safe Links and Safe Attachments

MFA blocks most stolen password attacks. Anti‑phish detects look‑alike domains and sender spoofing. Safe Links rewrites links and checks them at click time. Safe Attachments opens files in a sandbox first. Together they cut the biggest risks for SMEs with minimal fuss.

DMARC, SPF and DKIM explained (and how to set them up)

• SPF: lists which servers can send your mail. Add a TXT record like “v=spf1 include:spf.protection.outlook.com -all”.
• DKIM: signs your mail so receivers know it’s authentic. In Microsoft 365, enable DKIM for each domain and publish the CNAMEs in DNS.
• DMARC: tells receivers what to do if SPF/DKIM fail. Start “p=quarantine; rua=mailto:dmarc@yourdomain.com”, review reports, then move to “p=reject”.

If you use other senders (Xero, Mailchimp, CRMs), add their SPF/DKIM too. Test before switching DMARC to reject.

Microsoft 365 security baselines for busy teams

• Security Defaults or simple Conditional Access: require MFA, block legacy auth.
• Defender preset policies: apply “Standard” or “Strict” to users, execs, and finance.
• Mailbox governance: disable external forwarding, alert on inbox rule creation, restrict OAuth app consent.
• Admin controls: separate admin accounts, just‑in‑time elevation, and audit logging.
• Check Secure Score weekly. Aim for steady gains, not perfection on day one.

Staff training, simulations and incident response steps

• Training: 20–30 minute sessions each quarter. Show real Aussie scam examples and quick checks.
• Simulations: monthly tests with short debriefs. Reward good reporting.
• Incident response: reset passwords, revoke sessions, remove inbox rules, review sign‑ins, message trace, notify partners if needed, and switch DMARC to quarantine or reject if spoofing spikes.

What to outsource vs handle in‑house

• Handle in‑house: MFA rollout, Security Defaults, basic Defender presets, staff tips.
• Outsource: Conditional Access design, DMARC tuning across many mail senders, incident response, and ongoing monitoring. Managed support helps keep settings tight as staff and systems change. See managed IT support.

Common problems in Brisbane

Weather and infrastructure

• Summer storms and outages cause staff to check mail on personal devices. That’s when logins get phished. Use MFA and block legacy protocols.
• Humidity in older city buildings can knock out aging gear. Keep admin alerts on so you spot suspicious logins after reboots.
• NBN quirks: in parts of North Lakes, Redlands, and Springfield, latency spikes delay Safe Links checks. Keep patience; it’s better than a rushed click.
• Branch sites on 4G/5G during floods or roadworks often skip VPN. Apply Conditional Access by location and device compliance to reduce risk.

Troubleshooting and quick checks

Short answer

If you suspect a phish, stop sending, change your password, and approve MFA only from your own sign‑in. Check for new inbox rules and external forwarding. Run a message trace for unusual sends. Tell finance and your manager. If money is at risk, call the bank right away.

Quick checks

• Microsoft 365: Audit Log, Sign‑in logs, and Risky sign‑ins for your account.
• Mailbox: Rules, forwarding, delegates, and “Send As” rights.
• Defender: User submissions and Threat Explorer for look‑alike domains.
• DNS: Confirm SPF includes all real senders; DKIM is signing; DMARC policy is active.
• Vendors: Verify any bank detail change by phone to a known number, not the email thread.

Safety notes and when to call a pro

Red flags

Get help if payments were redirected, mail was sent from your account without you, or MFA prompts keep popping up. Also get help if DMARC blocks legit mail, you run many third‑party senders, or an exec mailbox was touched. Time matters; quick action saves cash and trust.

Local insights and examples

Brisbane/SEQ examples

We often see invoice fraud hit builders in Logan and Browns Plains near end‑of‑month. Real estate teams in Bulimba and New Farm cop look‑alike domains during Saturday opens. Health clinics in Sunnybank and Springfield get staff payroll changes from “HR” impostors. Simple checks and DMARC would have stopped most of these.

Storm season adds hiccups. When power flickers in Ipswich or Caboolture, staff jump to personal webmail and old passwords. With MFA and Safe Links, risky clicks drop, even on the mobile. Monthly simulations keep the habit fresh.

If you’re scaling across the Gold Coast or Moreton Bay with mixed NBN and LTE, set Conditional Access by country and device state. It limits risky logins when crews roam jobsites. For broader controls across devices and networks, see Internet Security.

FAQs

Q1: How do I set up DMARC, SPF and DKIM in Microsoft 365?

Add SPF as a TXT record with Microsoft 365’s include. In the Microsoft 365 admin, enable DKIM and publish the two CNAMEs at your DNS host. Create a DMARC TXT record at _dmarc.yourdomain with p=quarantine and a report address. Review reports, then move to p=reject.

Q2: What Microsoft 365 security settings should SMEs turn on today?

Require multi‑factor authentication, block legacy auth, and apply Defender anti‑phish, Safe Links, and Safe Attachments with preset policies. Disable auto‑forwarding externally, alert on inbox rule creation, and lock down admin roles. Use Conditional Access for location/device rules and check Secure Score weekly.

Q3: Do I need a third‑party gateway if I already have Microsoft Defender?

Many Brisbane SMEs run well on Defender Plan 1 or 2 with the right policies. A gateway can help if you need advanced quarantine control, archiving, or layered scanning. Test carefully to avoid double processing and delivery delays, and keep SPF/DKIM aligned for all senders.

Sources and further reading

Align your setup with the ACSC Essential Eight, OAIC Notifiable Data Breaches guidance, and ISO 27001 basics for access control and incident response. In Microsoft 365, use Secure Score as a simple roadmap. For email authentication, follow the flow: SPF and DKIM first, then DMARC from monitor to quarantine to reject.

Wrap-up and next steps

Turn on MFA, apply Defender presets, and set SPF/DKIM/DMARC. That alone cuts most phishing and business email compromise. Next, run short training and monthly simulations, and review Secure Score. If you want hands‑on help or ongoing monitoring, here’s the Brisbane‑ready link: Service:
Internet Security