Accountancy Sector
Cyber Threat Analysis
The UK accountancy industry is increasingly vulnerable to cyberattacks and data breaches due to the growing reliance on digital platforms and financial data storage. Accountancy firms manage highly sensitive information, including payroll, tax records, and financial statements, making them prime targets for cyber criminals seeking financial gain, identity theft, or fraud.
The rapid digitisation of financial records has also amplified the potential impact of a data breach, necessitating stringent cyber security measures.
91%
of accountants do not have Cyber Essentials certification
THE UK ACCOUNTANCY SECTOR IS A TOP TARGET.
Multiple high-profile UK accountancy firms suffered notable cyber incidents over the past 12 months, with ransomware and phishing attacks emerging as the most frequently reported threats.
The sector is experiencing a significant rise in cyber attacks, driven in part by gaps in staff training and overall industry preparedness, leaving sensitive client data increasingly at risk. Ransomware attacks now account for a growing proportion of incidents targeting accountancy firms, with double extortion tactics (data encryption + threat of public leaks) becoming a standard method used by attackers.
HIGH-PROFILE ACCOUNTANCY CYBER ATTACK EXAMPLES FROM RECENT YEARS:
+ Optionis Group Ltd/Caroola Group, UK
In January 2022, the UK accounting/contractor‑services group suffered one of the largest known ransomware attacks in the accountancy industry, forcing major brands under the group (e.g., SJD Accountancy, Nixon Williams, umbrella‑services firm Parasol Group) to suspend key IT systems. It’s reported that up to 28,000 clients were impacted and approximately 315,000 files (including management accounts, tax‑status letters, passport copies and payslips) were published on the dark web.
+ Sibbalds Chartered Accountants, UK
On 16 October 2025, the ransomware‑group Rhysida publicly claimed it had attacked Sibbalds, a UK‑based accountancy firm, and threatened to release sensitive data unless ransom negotiations begin. The incident highlights how attackers are increasingly targeting smaller professional services firms, leveraging double‑extortion tactics (encrypting systems + threatening to leak stolen data) to pressure victims.
+ Wojeski & Company, USA
In July 2023, Wojeski discovered a ransomware attack (likely triggered by a phishing email) that disrupted file access. A subsequent incident in May 2024 involved unauthorised access by a third‑party vendor, exposing the personal information of more than 4,700 New York residents (including names, Social Security numbers, driver’s licence numbers, financial‑account numbers, health‑insurance and medical benefits data) that had not been properly encrypted. The firm delayed notifying affected individuals for over a year and eventually settled with the New York Attorney General for a US $60,000 penalty, underlining the regulatory and operational risks of weak incident‑response and data‑protection practices.
ACCOUNTANCY SECTOR THREAT TRENDS:
Our recent analysis of the accountancy sector shows a growing prevalence of cyber incidents, with ransomware and phishing leading the threats. Many firms remain underprepared, with gaps in staff training and cyber security practices leaving them vulnerable to attacks that could compromise sensitive client data and disrupt operations.
43%
¼
No Regular Cyber Security Training
Nearly half of accountancy firms currently do not provide any form of regular cyber security training for their staff.
Untested Backups
Around a quarter of accountancy based firms admit to never testing their backups - leaving them potentially vulnerable to data loss and highlighting a significant cyber security gap within the sector.
Lack Essential Documents
Over a quarter of accountancy firms reportedly lack one or more essential cyber/information security documents such as an Information Security Policy, a Cyber Incident Response Plan or a Business Continuity Plan.
UNIQUE SECTOR CHALLENGES & RISKS:
+ Remote Work Shift - the shift towards remote work has further exposed firms to such threats due to reduced oversight and increased reliance on virtual communication.
+ Regulatory Compliance - firms must adhere to General data protection regulations (GDPR) and Financial Conduct Authority (FCA) regulations, with non-compliance resulting in substantial fines and reputational damage. A data breach not only compromises client information but also raises concerns about the firm’s ability to safeguard data in line with legal and ethical standards.
+ Internal Risks - including insider threats and employee errors, also pose a significant cyber security challenge. Employees, whether maliciously or unintentionally, may mishandle sensitive information, share login credentials, or fall victim to phishing scams. Without adequate training and security policies, firms remain vulnerable to breaches caused by human error.
WHAT METHODS ARE BEING EMPLOYED BY ATTACKERS?
+ Phishing Attacks
Phishing attacks employ deceptive emails, text messages or website links to try and trick individuals into revealing sensitive information like passwords or payment information.
Nearly half of financial sector organisations reported experiencing a phishing incident over the past 12 months.
+ Impersonation/Business Email Compromise (BEC)
Alarmingly, BEC accounted for 73% of reported cyber incidents among UK firms in 2024 - with over half of cases appearing within financial institutions. BEC is a form of targeted phishing attacks where a malicious actor poses as an employee, director or supplier for example, in order to gain unauthorised access to data or payments from unsuspecting employees using social engineering tactics.
+ Ransomware Attacks
Ransomware refers to a malicious software that encrypts a victim’s data and demands a ransom for its release. Cyber criminals will exploit vulnerabilities in outdated/unsupported legacy systems (commonly used by smaller/start-up firms) to gain network access and breach sensitive data.
In 2024, 56% of financial services organisations reported to have been hit by a ransomware attack/attempt.
+ Supply Chain Attacks
Significant providers in the industry (e.g. Quickbooks, Xero, Sage) can be targeted by cyber criminals to gain access to sensitive information. Attacks could be a stepping stone to subsequent attempts against users of the service, or downtime of the provider could directly disrupt operations.
Among UK based financial sector firms, around 60% suffered at least one third-party supply-chain attack in 2024.
HOW PURECYBER WILL SECURE YOUR ORGANISATION:
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Penetration Testing:
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Governance Support:
Ensuring your organisation is compliant with regulatory requirements and expectations is the backbone of your organisational cyber security. As an NCSC Certified Assurance Provider, our consultancy services offer guidance and support in improving organisations cyber policies, achieving accreditations, auditing cyber posture and approach and reaching compliance standards.
Our certified team of Lead Auditors, Lead Implementors, and CISSP consultants are here to guide and support you on all aspect of your cyber security compliance needs including consultancy on CE, CEP & IASME, ISO27001, Incident Response Simulation, Cyber Security Audits, vCISO & Awareness Training.
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