Top 5 Cyber Threats to Australian Small Businesses (2025): What Leaders Need to Know

Cyber as a Business Continuity Risk

Many Small and Medium Business leaders believe cybersecurity risk is an IT issue. However it is much broader – ultimately it is a business continuity issue. Cybersecurity incidents can derail cashflow, reputation, and legal compliance. Just last month a pharmacy in regional Queensland was impacted by a ransomware incident that disrupted operations, highlighting the common trend of targeting under-secured small businesses.

Boards and Executive teams have a duty of care under legislative and regulatory frameworks including the Corporations Act and Privacy Act, and in some cases APRA CPS 234 (information security) and CPS 230 (operational risk). Even if your security requirements aren’t directly regulated, your customers or service providers often are, and risk flows both ways.

Attackers today are lean, smart, and relentlessly leveraging AI. They automate attacks against unpatched software, reused credentials, or email accounts without multi-factor protection. That’s why small organisations get hit disproportionately: they are easier targets.

Most cybersecurity attacks target known, fixable gaps. If you focus on the classic high-leverage controls such as multi-factor authentication (MFA), patch discipline, vendor oversight, backups, and staff awareness, you can address a large proportion of your risk. These are not expensive tools and processes. They are operational controls rooted in the ASD’s Essential Eight framework and aligned with the internationally recognised standard ISO/IEC 27001. Synergy Compliance can help implement these.

In this post we’ll walk you through the five most common cyber threats Australian SMBs face, show you what to watch for, and map clear, realistic actions you can take even with limited resources.

1. Email Compromise & Phishing: the Everyday Con Trick

Email-based attacks remain the most common pathway for cybercrime. According to ACSC, “email compromise (no financial loss)” represents ~20% of reported business incidents.
When email accounts are tricked or hijacked, criminals use them to request fraudulent payments or direct staff to unsafe sites. Attackers increasingly use AI to craft highly convincing phishing messages and voice impersonations – this is known as spear phishing.

Warning signs:

• An unexpected email from a supplier changing their bank or payment details
• Forwarding rules or login notices suddenly appear in your account
• Emails received have an odd tone or domain typos

What you can do:

• Enforce multi-factor authentication (MFA) across all email accounts
• Train staff to call suppliers to verify any payment changes
• Implement DMARC / SPF / DKIM to reduce spoofing
• Use simple approval workflows for any invoice changes

These steps align with Essential Eight (User Application Hardening, MFA) and ISO 27001 (access control). If your organisation is subject to APRA CPS 234, these are foundational controls you must embed.

2. Ransomware & Data Extortion: Holding You to Ransom

Ransomware involves hackers infiltrating your network and encrypting critical files so you can’t access them until a ransom is paid. Small businesses are prime targets because their defences are often weaker, and the impact of the attack can shut down entire operations for days or longer. Victims face expensive downtime, recovery costs and sometimes permanent data loss. There’s no guarantee your data will be restored. The data can be used as leverage, threatening to leak sensitive information if demands aren’t met. This double-extortion tactic often leads to legal and reputational fallout.

Real Case: MediSecure Collapse After Ransomware Breach (2024)
In late 2023, e-prescription provider MediSecure fell victim to a large-scale ransomware attack that exposed sensitive personal and health data of 12.9 million Australians. This was one of the largest breaches in Australian history. Weeks later, the company went into voluntary administration (June 2024) after failing to secure a federal bailout. “By the time this breach happened, MediSecure had lost its main source of revenue,” noted CyberCX, underscoring how the attack hit an already vulnerable business.

Detection signs:

• Files renamed or locked
• Sudden deletion of backups
• Systems slowing or rebooting unexpectedly

Defence and preparation:

• Maintain robust 3-2-1 backups (one copy offline)
• Patch critical systems promptly (and restart laptops!)
• Limit privileges, disable unnecessary macros
• Rehearse incident-response playbooks

These protections will minimise downtime, rebuild costs, reputation damage and support your compliance with the Privacy Act and Notifiable Data Breaches scheme.

3. Stolen Credentials & Account Takeover: The Invisible Breach

Many breaches never “look like a hack” – they begin with credential theft. The OAIC’s Jul–Dec 2024 NDB report lists 84 notifications caused by phishing (compromised credentials) – the leading breach cause. Attackers often use these credentials to move deeper into systems, exfiltrate data, or impersonate users.

Warning signs:

• Multiple MFA requests
• Login attempts from foreign IPs
• New API tokens or admin accounts you didn’t initiate

Controls you should adopt:

• Mandate MFA on all cloud, email, and critical systems
• Use a password manager + strong passphrases
• Disable legacy/basic authentication
• Periodically audit access rights

These are central to Essential Eight controls and ISO 27001 access and identity management strategies.

4. Supply-Chain & Vendor Risk

As businesses become ever more interconnected with vendors and service providers, a cyber incident in your supply chain can quickly become your problem. Hackers may target a smaller third-party provider as a backdoor into your network or to simply disrupt your operations by knocking out a key supplier. For example, if an IT platform you rely on is breached, your data could be exposed. If a logistics partner goes down, you may not be able to deliver products. The ripple effects of a single supplier’s compromise can be devastating for a small business and hard to recover from.

Real Case: Barnett’s Couriers Shuts Down After Cyber Attack (2024)
In May 2024, after 40 years in business, Wollongong-based Barnett’s Couriers abruptly shut its doors, blaming a crippling cyber attack for the company’s demise. Employees were given only hours’ notice of the closure. A recorded message to customers explained that despite “working tirelessly” with IT consultants, the company was unable to restore systems and had made the “difficult decision to cease operating”. “It’s very concerning, and very strange for a company to close so suddenly because of cyber attack,” commented Transport Workers’ Union official, highlighting the unprecedented nature of the incident.

Red flags:

• Vendor outage announcements
• Unexpected OAuth consents
• New vendor accounts or integration activity

What to do:

• Keep a vendor register with data access details & location
• Require MFA, backup, and incident notice clauses in contracts
• Review vendor access frequently, such as quarterly

5. Patching & Vulnerability Management: The Basic Door Still Opens

Many attacks succeed because systems aren’t up to date. ACSC notes a 31% rise in public vulnerability disclosures (CVEs), exploited quickly by attackers.

Symptoms:

• Vendor alerts for “critical patch required”
• Unexpected system crashes
• New admin accounts or services you didn’t install

Your minimal viable defence:

• Turn on automatic updates wherever possible
• Close or restrict administrative interfaces (RDP, VPN)
• Use standard user accounts (not admin) for day-to-day work
• Track major patches in a simple schedule

These controls map directly to Essential Eight (patching) and ISO 27001 technical vulnerability management.

Bringing it Together – Security, Resilience and Compliance

Cyber threats in 2025 are daunting but not insurmountable. By staying vigilant and proactively shoring up defences – from training staff to securing your systems and vetting suppliers – small businesses can greatly reduce their risk of falling victim. Cybersecurity isn’t just an IT issue; it’s a core business survival issue. The good news is that with the right precautions and a strong compliance mindset, even the smallest company can ward off attacks and keep its operations running securely.

For next steps: engage your board, benchmark against industry standards, and lean on Synergy Compliance to guide you through.

Actionable Takeaways for Leaders

• Mandate MFA for email, cloud and financial systems.
• Audit your vendor register and embed security + notification clauses.
• Ensure automatic patching or monthly patch cycles for all software.
• Rehearse a tabletop breach scenario – identify roles and escalations.