By PPCS — IT Support & Cybersecurity for Accountants in Hampshire, Surrey & Berkshire

Accounting firms manage some of the most sensitive information in the UK economy: tax records, payroll data, bank details, and confidential client communications. That makes practices of all sizes a high-value target for attackers. Over the past few years, professional services have reported a marked rise in phishing, credential theft, and ransomware incidents — often exploiting basic gaps that can be closed with straightforward controls. At PPCS, we help accounting and professional-services firms achieve Cyber Essentials and ISO 27001 readiness, harden Microsoft 365, implement secure backup and recovery, train teams, and adopt continuous monitoring. This pillar article explains the five most common cybersecurity mistakes we see in accounting practices — and how to fix them without disrupting fee-earning work.

Mistake 1: Treating Cyber Essentials as a one-time tick box

Cyber Essentials is an excellent baseline, but it reflects a point-in-time assessment. Threats evolve weekly. If patching, configuration, and access controls are not reviewed regularly, your posture can drift below the minimum standard long before your next renewal.

How to fix it

  1. Use Cyber Essentials as a foundation for continuous improvement, not a finish line.
  2. Upgrade to Cyber Essentials Plus for independent validation and hands-on testing.
  3. Schedule quarterly reviews of patching, asset inventory, firewalls, and endpoint protection.
  4. Layer in 24/7 monitoring to detect account compromise, unusual logins, and data exfiltration.

Mistake 2: Weak passwords and poor access control

Shared logins, reused passwords, and inactive accounts are a fast track to compromise. Most attackers do not “hack in” — they log in using harvested credentials. For practices handling confidential client data, this is both a security and a GDPR risk.

How to fix it

  1. Enable multi-factor authentication (MFA) on email, cloud apps, remote access, and practice software.
  2. Adopt a password manager to generate and store unique credentials.
  3. Implement role-based access control (RBAC) and review access quarterly.
  4. Disable or remove accounts for leavers immediately; audit shared mailboxes and service accounts.
  5. Consider conditional access in Microsoft 365 Business Premium (location/device-based rules).

Mistake 3: No ongoing staff awareness and phishing training

The majority of breaches begin with a human mistake, often a convincing email that imitates HMRC, Companies House, a supplier, or a client. One-off induction modules do not build lasting habits; awareness must be continuous and contextual.

How to fix it

  1. Run quarterly phishing simulations with measurement and feedback.
  2. Deliver short, role-relevant micro-learning rather than long annual videos.
  3. Encourage a no-blame reporting culture to surface suspicious emails quickly.
  4. Reinforce with lightweight reminders via Teams, Slack, or internal newsletters.

Mistake 4: Inadequate backup and disaster recovery

Ransomware and accidental deletion are routine hazards. Local NAS devices alone are often connected to the same network and can be encrypted alongside primary data. Your backup strategy should prioritise immutability, separation, and successful restoration — not just storage volume.

How to fix it

  1. Apply the 3-2-1 rule: three copies of data, two different media types, one offsite or cloud.
  2. Automate daily backups; encrypt in transit and at rest; monitor for failures.
  3. Test restores at least twice per year and document expected recovery times.
  4. Use UK-hosted, compliant cloud options where data residency is required.

Mistake 5: No incident response plan or continuous monitoring

Without real-time visibility, breaches often go undetected for months. When something goes wrong, firms without a plan lose time deciding who does what, who informs clients, and how to recover safely.

How to fix it

  1. Create and maintain a written incident response plan with clear roles and escalation paths.
  2. Store emergency contacts and critical playbooks offline.
  3. Adopt Managed Detection & Response (MDR) or SIEM-backed monitoring to spot unusual activity.
  4. Run annual tabletop exercises to validate communications and technical recovery steps.

Compliance and client expectations

Under UK GDPR, firms must implement appropriate technical and organisational measures, maintain records of processing, and report certain breaches. Clients increasingly assess suppliers on security maturity during tenders and due diligence. Demonstrating Cyber Essentials Plus and alignment with ISO 27001 can accelerate sales cycles and reassure stakeholders.

  1. Maintain up-to-date Data Protection Impact Assessments (DPIAs) and data-flow maps.
  2. Align policies and risk management with ISO 27001 control families.
  3. Publish your certifications and summary controls to build trust with clients.

A simple maturity framework for accounting firms

Stage Focus Typical Situation
1 — Reactive Minimal controls Antivirus only; ad-hoc updates; unmanaged passwords
2 — Compliant Baseline certification Cyber Essentials achieved; limited monitoring
3 — Managed Proactive defence MFA, backups, awareness training in place
4 — Resilient Continuous monitoring MDR/SIEM, incident playbooks, tested restores
5 — Optimised Continuous improvement ISO 27001 alignment; automated reporting and audits

Download the full PPCS white paper

This blog offers a concise overview. The PPCS White Paper goes deeper with practical checklists, incident-response templates, and real-world scenarios from UK accounting firms.

  1. Cyber Essentials to Cyber Essentials Plus roadmap
  2. Microsoft 365 hardening quick-wins
  3. 3-2-1 backup checklist and restore testing plan
  4. Staff awareness and phishing-simulation schedule
  5. Incident response roles and communications outline

About PPCS

Prime PC Services (PPCS) is a specialist IT and cybersecurity partner for accounting and professional-services firms across Hampshire, Surrey, and Berkshire. We provide proactive support, Cyber Essentials and Plus certification support, ISO 27001 readiness, Microsoft 365 hardening, secure backup and recovery, staff awareness programmes, and 24/7 monitoring.

Contact us for a free Cyber Risk Review or to discuss certification options.

Tel: 07756 79 79 55   |   Email: hello@ppcs.uk

FAQs

Is Cyber Essentials enough for an accounting firm?

It is a strong baseline for technical controls, but it does not provide continuous assurance. Add ongoing monitoring, regular patching, MFA, backups, and staff training. Cyber Essentials Plus provides independent testing and stronger evidence for clients.

What should be protected with MFA?

Enable MFA on Microsoft 365, email, remote desktop, VPN, practice management, client portals, and any application that stores or transmits client data.

How often should we test backups?

Backups should be monitored daily and restore tests performed at least twice per year. Document recovery time objectives around peak periods such as self-assessment season.

Do we need an incident response plan?

Yes. A written plan with defined roles, containment steps, client and regulator communications, and recovery procedures reduces downtime and legal risk.

Will ISO 27001 help us win clients?

Alignment with ISO 27001 and a current Cyber Essentials Plus certificate are increasingly requested in tenders and supplier questionnaires. They demonstrate governance and control maturity.