The Biggest Cyber Security Threats Facing UK Businesses in 2026

October is Cyber Security Awareness Month, making it a good time for organisations to review the risks they face and the steps they are taking to protect their people, systems and data.

Cyber attacks are not limited to large corporations or businesses handling millions of customer records. Small and medium-sized organisations are regularly targeted because they hold valuable information, process payments and often have fewer internal cyber security resources.

The UK Government’s Cyber Security Breaches Survey 2025/26 found that 43% of UK businesses had experienced a cyber security breach or attack during the previous 12 months. For medium-sized businesses, that increased to 65%, while 69% of large businesses identified a breach or attack.

For businesses in Portsmouth, Chichester and across the South of England, cyber security therefore needs to be treated as an everyday business priority.

As part of Cyber Security Awareness Month, we are looking at some of the most significant cyber threats facing UK businesses in 2026 and the practical actions organisations can take to reduce their risk.

AI-Powered Phishing Attacks

Phishing remains the most common cyber threat facing UK businesses. According to the latest UK Government survey, 38% of businesses experienced phishing during the previous 12 months.

Phishing emails have traditionally contained warning signs such as poor spelling, unusual language or obvious formatting mistakes. Generative AI is making those signs much harder to spot.

Criminals can now create convincing emails that imitate a person’s tone, refer to genuine organisations and contain detailed information gathered from websites or social media. They can produce these messages quickly and adapt them for different employees, industries and situations.

A phishing message might appear to come from a colleague asking someone to review a document, Microsoft requesting an account login or a supplier sharing a new invoice.

Businesses should use effective email filtering, multi-factor authentication and regular cyber security awareness training. Employees also need to understand that modern phishing attempts may appear polished and professional. Good spelling is no longer evidence that an email is genuine.

Business Email Compromise and Payment Fraud

Business email compromise is a particularly damaging form of impersonation.

An attacker may gain access to a genuine email account or create a convincing imitation of one. They then monitor conversations, learn how the organisation works and wait for an opportunity to request a payment or change bank details.

Finance teams, senior leaders and employees with access to sensitive information are often targeted. However, any compromised account can help an attacker build a convincing story.

These attacks succeed because the request often appears to come from someone the recipient already trusts.

Businesses should introduce a separate verification process for payment requests and changes to supplier bank details. For example, employees should call a known contact using a telephone number already held on file rather than relying on the details in the email.

Ransomware and Data Extortion

Ransomware remains one of the most serious threats to UK organisations. It can encrypt files, disable systems and leave employees unable to access the information they need to work.

Modern ransomware attacks frequently go beyond encryption. Criminals may steal sensitive information before locking the systems and then threaten to publish it if a ransom is not paid.

This creates several risks at once:

• Operational disruption
• Loss of important data
• Financial demands
• Regulatory consequences
• Damage to customer confidence
• Reputational harm

Ransomware groups do not always choose victims based on their size or sector. They often look for organisations with vulnerable systems, stolen login credentials or weak remote-access controls.

Reliable backups are essential, but they must be protected from the main network and tested regularly. There is little value in having a backup if it has also been encrypted or nobody knows whether it can be restored.

Pronetic’s business continuity and disaster recovery services help organisations prepare for disruption and recover critical systems when an incident occurs.

Stolen Passwords and Identity-Based Attacks

Attackers do not always need to break through a firewall. It may be easier to sign in using a genuine employee’s details.

Passwords can be obtained through phishing websites, malware, previous data breaches or password reuse. Once criminals have access to an email or Microsoft 365 account, they may be able to read messages, download information and impersonate the user.

Multi-factor authentication provides an important extra layer of protection, but attackers are also finding ways to target it. This includes sending repeated approval requests until the employee accepts one or convincing an IT helpdesk to reset an account.

Every business should use strong, unique passwords and multi-factor authentication wherever it is available. Access should also follow the principle of least privilege, which means employees only receive the permissions they genuinely need.

Suspicious sign-ins and unusual account activity should be monitored so that compromised accounts can be identified quickly.

Unpatched Software and Devices

Software vulnerabilities are regularly discovered in operating systems, applications, firewalls and remote-access tools.

Once a vulnerability becomes public, criminals can begin scanning for businesses that have not installed the relevant security update. Delaying an important patch can leave a known route into the organisation available for attackers to exploit.

This risk is not limited to laptops and servers. Mobile devices, networking equipment and other connected technology also need to be updated and managed.

A professional provider of IT support in Portsmouth can monitor devices, manage security updates and identify problems before they develop into larger incidents.

Pronetic’s managed device security service provides ongoing visibility and protection for company devices, whether employees are working in the office, at home or while travelling.

Supply-Chain Attacks

Most organisations rely on external suppliers, software platforms and technology partners. Each connection can introduce another potential route into the business.

A supply-chain attack occurs when criminals compromise a trusted supplier and use that access to reach its customers. One successful attack may therefore affect many different organisations.

Businesses should understand which suppliers have access to their systems and information. This is particularly important for providers that handle sensitive data, process payments or hold privileged access to the IT environment.

Supplier reviews should consider:

• What information the supplier can access
• How that access is protected
• Whether multi-factor authentication is required
• How security incidents will be reported
• What cyber security standards the supplier follows
• How access will be removed when the relationship ends

Holding Cyber Essentials, Cyber Essentials Plus or ISO 27001 certification can help a supplier demonstrate that recognised security controls are in place.

As a Cyber Essentials Plus-accredited and ISO 27001-certified IT provider, Pronetic understands the importance of protecting customer information and maintaining strong security processes.

Cloud and Microsoft 365 Security Risks

Microsoft 365 has become central to the way many organisations communicate, collaborate and store information.

That also makes Microsoft accounts attractive targets.

Weak access controls, excessive permissions and poorly protected accounts can expose emails, documents and other sensitive information. Criminals who gain access may create forwarding rules, download files or send convincing messages from the compromised account.

Cloud security requires more than setting up Microsoft 365 and leaving it to run. Permissions, identity controls, security policies and account activity should be reviewed regularly.

Pronetic’s Microsoft 365 Threat Detection and Response service helps businesses identify unusual behaviour and respond to potential threats within their Microsoft environment.

Deepfake Voice and Video Scams

AI-generated audio and video are creating new opportunities for fraud.

An employee may receive a voice message that appears to come from a director requesting an urgent payment. A video call could feature a convincing imitation of a known colleague. Criminals can use publicly available recordings and images to make these attempts more believable.

Businesses should never rely solely on someone’s voice, image or apparent email address when authorising a sensitive request.

Clear approval processes and separate checks remain essential. If a request is unexpected, confidential or unusually urgent, employees should confirm it using another trusted communication channel.

Creating a culture where people feel comfortable questioning senior employees can make a significant difference. Staff should not be criticised for taking a few minutes to check whether a request is genuine.

Shadow AI and Accidental Data Leakage

Employees are increasingly using AI tools to summarise documents, draft emails and analyse business information.

If these tools have not been approved by the organisation, employees may accidentally upload customer records, contracts, financial information or other confidential data to an external platform.

This is sometimes described as “shadow AI”.

Blocking every AI tool is unlikely to provide a complete answer. Employees need clear guidance explaining which platforms are approved, what information they can use and when AI-generated work must be reviewed.

Businesses should also review their data permissions before introducing tools such as Microsoft Copilot. AI works with the information users can already access, which means disorganised permissions could allow sensitive information to appear in unexpected places.

The Pronetic AI Hub includes practical guidance on AI adoption, security and governance for organisations that want to use AI without increasing risk.

Mobile, Text and QR-Code Scams

Not every phishing attempt arrives through company email.

Criminals use text messages, messaging apps and QR codes to direct employees to false login pages. These attacks can be particularly effective on mobile devices because the smaller screen makes it harder to inspect a link or check the sender’s address.

QR codes may appear on posters, invoices, parking notices or even inside emails. Scanning the code can take the user away from the organisation’s usual email protection and directly to a malicious website.

Employees should be encouraged to treat unexpected QR codes and text messages with the same caution as suspicious emails.

What Should Businesses Do During Cyber Security Awareness Month?

Cyber Security Awareness Month should lead to practical action rather than simply another reminder to be careful online.

October is a good opportunity to:

• Review account permissions and remove unnecessary access
• Enable multi-factor authentication
• Check that security updates are being installed
• Test backups and recovery procedures
• Review Microsoft 365 security settings
• Run current cyber security awareness training
• Check how supplier payment changes are verified
• Introduce an approved AI usage policy
• Review the security of important suppliers
• Update and test the cyber incident response plan
• Consider working towards Cyber Essentials or Cyber Essentials Plus

Employees should also know how to report a suspicious email, unexpected login request or potential mistake. Reporting an incident quickly gives the business a much better chance of limiting the damage.

Protect Your Business With Local Cyber Security Support

The methods used by cybercriminals continue to change, but the foundations of good protection remain consistent.

Secure accounts, updated devices, controlled access, reliable backups and informed employees can prevent many common attacks. Businesses also need ongoing monitoring and a clear plan for responding when something goes wrong.

Pronetic provides compliance-led cyber security and IT support to businesses across Portsmouth, Chichester and the surrounding areas. Our team can help you understand your current risks, strengthen your security controls and build a more resilient IT environment.

Whether you need cyber security awareness training, managed device protection, Microsoft 365 security or support with Cyber Essentials Plus, we will give you clear, practical guidance without unnecessary jargon.

Speak to Pronetic about protecting your organisation during Cyber Security Awareness Month and beyond.