Top 5 cyber threats facing accountants in 2025

As we move further into 2025, the landscape of cyber threats continues to evolve. With the growing use of digital tools and the increasing sophistication of cybercriminals, accountants must be vigilant in identifying and proactively mitigating these risks. This article explores the most significant cyber threats facing accountants in 2025, their potential impacts, and practical ways to keep your business stay safe.

1. Ransomware attacks

Ransomware remains one of the most formidable threats to accountancy practices in 2025. Cybercriminals are increasingly targeting businesses that handle sensitive financial data, knowing that the potential for profit is high. In a ransomware attack, hackers encrypt a firm's data and ask for a ransom to unlock it. 

Impact:

The financial implications can be substantial. According to the UK’s National Cyber Security Centre (NCSC), ransomware attacks are projected to cost UK businesses over £1 billion annually. For accountants, this can mean prolonged downtime, loss of client trust, and significant financial losses. Firms may find themselves unable to access critical financial records during peak periods, such as tax season.

How to stay safe:

• Regular backups: Implement a robust data backup strategy, storing backups securely, preferably offline or in a separate cloud environment.
• Employee training: Regular training sessions on recognising phishing attempts and other cyber threats to help reduce the risk of ransomware infections.
• Incident response plan: Creating a clear incident response plan ensures quick and effective action if a ransomware attack occurs.

2. Phishing and social engineering attacks

Phishing attacks are becoming more sophisticated, with cybercriminals using social engineering tactics to trick employees into divulging sensitive information. Accountants should be particularly mindful of these tactics, as attackers often impersonate trusted sources, such as clients or colleagues.

Impact:

Phishing attacks can lead to data breaches and financial losses. The 2023 Cybersecurity Breaches Survey revealed that 84% of UK businesses reported experiencing phishing attacks and this trend is set to continue. For accountants, falling victim to a phishing scam can result in the exposure of sensitive client information, leading to potential legal ramifications and loss of client trust.

How to stay safe:

• Security awareness training: Regular training for employees on recognising phishing attempts and social engineering tactics is crucial. This training should include real-world examples relevant to the accounting industry.
• Multi-factor authentication (MFA): Implementing MFA adds an extra layer of security, making it more difficult for attackers to gain access to sensitive systems, even if they obtain login credentials.

3. Data breaches and insider threats

As custodians of sensitive financial information, accountants are prime targets for data breaches. In 2025, the risk of data breaches will continue to rise, driven by the increasing sophistication of cybercriminals and the prevalence of insider threats. Insider threats can arise from employees who inadvertently compromise data security or those who act maliciously.

Impact:

The fallout from a data breach can be severe, including loss of client trust and significant remediation costs. According to IBM's Cost of a Data Breach Report 2023, the average cost of a data breach in the UK is approximately £3.86 million.

How to stay safe:

• Access controls: Implement strict access controls based on job roles to limit exposure to sensitive data.
• Regular audits: Conduct regular audits of data access and usage to identify potential insider threats.

4. Business Email Compromise (BEC)

Business Email Compromise (BEC) is a sophisticated scam that targets businesses, particularly in the financial sector. In 2025, BEC attacks are expected to become more prevalent, with cybercriminals impersonating executives or trusted partners to trick employees into transferring funds or sharing sensitive information.

Impact:

BEC scams can lead to financial losses for accounting firms. For accountants, the risk is particularly acute, as they often handle large transactions and sensitive financial information.

How to stay safe:

• Verification procedures: Establish strict verification procedures for financial transactions to prevent BEC scams. Employees should be trained to verify requests for fund transfers through multiple channels.
• Email security solutions: Implement advanced email security solutions to detect and block phishing attempts and BEC scams before they reach employees' inboxes.

5. Supply chain attacks

As accounting firms increasingly rely on third-party vendors for various services, the risk of supply chain attacks is on the rise. Cybercriminals may target software providers or cloud services used by accounting firms to gain access to sensitive data.

Impact:

Supply chain attacks can lead to data breaches and operational disruptions. For accountants, the consequences can include loss of client trust, regulatory penalties, and remediation costs.

How to stay safe:

• Vendor risk management: Implement a robust vendor risk management programme to assess the security posture of third-party vendors.
• Data encryption: Encrypt sensitive data both in transit and at rest to protect against supply chain attacks.

How else can you protect your practice?

In addition to implementing robust cybersecurity measures, investing in cyber insurance can be a vital part of your risk management strategy. It provides financial protection against the costs associated with cyber incidents, helping you to recover from an attack and reduce their impact.

What does cyber insurance cover?

A cyber insurance policy typically includes two main types of cover:

• First-party cover: This includes costs associated with responding to a cyber incident, such as forensic investigations, legal fees, and business interruption losses.
• Third-party cover: If a data breach affects clients or other third parties, this coverage can help with legal expenses and claims related to negligence.

How does cyber insurance work when you need it?

When a cyber incident occurs, the process for making a claim usually involves:

1. Immediate notification: Notify the insurance provider as soon as a cyber incident is detected.
2. Access to resources: The insurance provider will often provide access to a 24/7 hotline for immediate assistance.
3. Investigation and assessment: The insurance provider may conduct an investigation to assess the extent of the damage.
4. Coverage of costs: Once the claim is approved, the insurance provider will cover the costs associated with the incident.
5. Post-incident support: Many policies offer post-incident support, including resources for improving cybersecurity measures.

While most professional indemnity insurance offers some level of cyber cover, it is unlikely to cover all types of cyber incidents, such as ransomware attacks, data breaches, or business interruption due to cyber events. A standalone cyber policy is specifically designed to address these risks comprehensively, improving your practice's resilience against cyber threats.

By understanding the most significant cyber risks you face in 2025, implementing effective strategies, and investing in cyber insurance, it is possible to protect your practice and their clients from the impacts of cyber incidents.

Talk to a cyber insurance expert today

If you’d like to find out more about how to manage your cyber risks and protect against threats, contact our ICAEW team on 0345 894 4684 or get in touch here.

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