A convincing invoice, a Microsoft 365 password alert or an urgent request from a director can reach an employee between meetings and be acted on in seconds. That is why learning how to prevent phishing emails is not simply an IT task. It is a practical part of protecting cashflow, confidential data, client trust and the ability to keep operating normally.
Phishing has moved well beyond poorly written messages from unfamiliar senders. Criminals now copy supplier branding, imitate senior colleagues and use compromised accounts to send messages from genuine-looking addresses. For small and medium-sized businesses, the most effective response combines technical protection with clear, repeatable staff habits. Neither works as well on its own.
Why phishing remains a business risk
Phishing emails are designed to make people do one of three things: disclose a password, open a harmful attachment or make a payment. A successful attack may give a criminal access to Microsoft 365, payroll records, customer information or financial systems. In some cases, the first email is only the starting point for a wider ransomware or business email compromise incident.
The commercial impact can be immediate. A fraudulent payment may be difficult to recover; a compromised account can send further phishing emails to customers and suppliers; and downtime can disrupt delivery, billing or client service. Regulated organisations also need to consider their responsibilities for personal and sensitive information.
The challenge is that a phishing email does not always look suspicious at first glance. Staff are busy, suppliers change bank details legitimately, and messages from cloud services can be frequent. Your controls need to account for real working conditions, rather than expecting every employee to spot every threat perfectly.
How to prevent phishing emails with layered protection
There is no single setting that stops all phishing. The sensible approach is to build layers, so that if one control is bypassed, another limits the damage.
Filter malicious messages before they reach inboxes
Email protection should scan incoming messages for malicious links, attachments, spoofed senders and known phishing techniques. It should also examine messages sent internally, because a compromised colleague’s account can be especially convincing.
For organisations using Microsoft 365, security settings should be configured for the way your business actually works. Overly strict filtering can delay legitimate supplier emails, while loose settings leave staff exposed. The aim is not to block every unusual message. It is to reduce the number of dangerous messages that employees ever need to assess.
Domain protection is also worth addressing. Properly configured email authentication helps receiving systems check whether a message claiming to come from your domain is genuine. This reduces the chance of criminals impersonating your business to target customers, suppliers or your own staff.
Make stolen passwords less useful
A password entered on a fake sign-in page can give an attacker a route into an account within minutes. Multi-factor authentication, ideally using an authenticator app or security key, makes that stolen password far less valuable.
It is not a complete answer. Criminals may use fake sign-in pages that request a multi-factor approval, or steal session information from an infected device. However, multi-factor authentication remains one of the strongest practical safeguards against routine account takeover. It should be enabled for email, finance systems, remote access and any application holding sensitive business information.
Strong, unique passwords matter too. A credential manager helps staff use them without resorting to reused passwords, notebooks or predictable variations. If a password is exposed in an unrelated breach, reuse can turn one incident into access across several business services.
Secure the devices people use to read email
Phishing does not only target inboxes. A harmful attachment or link can attempt to install malware on the device that opens it. Managed endpoint protection, prompt security updates and controlled software installation reduce that risk.
Web browsing protection adds another useful layer by blocking known malicious websites, including fake Microsoft 365 sign-in pages. This matters when an email slips through filtering or when an employee receives a phishing link through a messaging platform rather than email.
For remote and hybrid teams, make sure the same protections apply outside the office. A home laptop, personal mobile device or unmanaged computer can become the weak point if it accesses company email without suitable controls.
Give staff a simple way to spot phishing
Training works best when it is practical, brief and repeated. A yearly presentation may satisfy a policy requirement, but it will not prepare someone for a credible email received late on a Friday afternoon. Staff need examples that reflect their roles, such as invoice fraud for accounts teams, document-sharing requests for professional services or delivery-related messages for operational teams.
Encourage employees to pause when a message creates urgency, secrecy or pressure. They should check the sender address carefully, inspect unexpected links before opening them and be cautious with attachments they were not expecting. A polished logo or familiar name is not proof that an email is safe.
The following warning signs should prompt a second check:
- a request to reset a password or approve multi-factor authentication that the recipient did not initiate;
- changed bank details, especially where payment is requested urgently;
- unexpected shared files, invoices or scanned documents;
- messages that move a conversation away from normal approval processes; and
- small changes in an email address, spelling or domain name.
These signs are useful, but context matters. A genuine supplier may send an unexpected invoice. The right response is not necessarily to ignore it, but to verify it through a trusted route, such as a known telephone number or an existing contact record. Do not use the contact details in the suspicious email itself.
Make reporting easy and blame-free
Employees should know exactly what to do when they are unsure. A clear reporting button or a designated address can help, but the culture around it matters just as much. People must feel comfortable reporting a suspicious message, even if they clicked a link or entered details.
Treating reports as a learning opportunity allows your IT team or managed provider to investigate quickly, remove similar emails from other inboxes and reset credentials where needed. Blame and embarrassment encourage silence, which gives an attacker more time.
Protect high-risk processes outside the inbox
Many phishing attacks succeed because an email triggers a weak business process, not because technology failed. Payment changes, new payees and requests to release funds should require independent verification and clear approval steps. A request apparently from a director should not override established controls simply because it sounds urgent.
The same principle applies to access requests. No member of staff should add a new administrator, share confidential files externally or disclose client information on the basis of an emailed instruction alone. For sensitive actions, use a separate channel to confirm identity.
Senior leaders and finance staff often receive the most carefully targeted messages. They need the same training and protections as everyone else, alongside procedures that make it acceptable to challenge a request from a colleague or partner.
Know what to do if someone clicks
Speed matters after a suspected phishing incident. Staff should report it immediately, disconnect a device from the network if malware is suspected, and avoid deleting the message before it can be checked. If credentials were entered, reset the password through a known route and review active sessions and multi-factor settings promptly.
Your incident process should identify who investigates, who communicates with affected customers or suppliers if required, and when to involve specialist support. Keep this process proportionate to your organisation, but test it occasionally. A plan that exists only in a policy folder rarely helps when people are under pressure.
Reliable backups are part of resilience too. They will not stop a phishing email, but they can reduce disruption if an attack leads to ransomware or data loss. Backups should be protected, monitored and tested for restoration, not simply assumed to be available.
Turn phishing prevention into routine business practice
The best phishing defences are visible in everyday behaviour: staff pause before acting, systems challenge suspicious activity, and leaders support verification rather than rushing decisions. Review your email security, account protection and payment processes as your business changes, particularly when introducing new cloud tools, suppliers or remote-working arrangements.
For businesses without in-house security expertise, a managed approach can take pressure away from busy leaders. MSnet can help combine email and endpoint protection with practical awareness training and responsive human support, so protection is maintained rather than left as a one-off project.
A suspicious email will eventually reach someone in your organisation. The goal is to make sure that one click, one rushed reply or one convincing impersonation does not become a business-critical event.