Cyber Attack on Law Firms in the UK

UK Law firms are no strangers to the threat of cyber-attacks. Cyber-attacks on law firms in the UK have surged by 77% in the past year, rising from 538 incidents in 2022/23 to 954 in 2023/24 according to Crowe. As the legal sector undergoes rapid digital transformation, cybercriminals are exploiting gaps in cyber security to access high-value information and disrupt business operations.

This post is the first in a three-part blog series focused on cyber security for UK law firms. In this opening guide, we explore why law firms are facing a surge in cyber threats, the most common types of attacks, real-world breaches, and what makes the legal sector such an appealing target. The second post dives into how AI is both enabling cybercriminals and empowering defenders, while the final post will outline actionable solutions law firms can adopt to strengthen their security posture and build long-term resilience.

Why Are UK Law Firms Targeted in Cyber Attacks?

1. High Value Data

Law firms are data-rich organisations, trusted with everything from confidential contracts and intellectual property to client identities and litigation strategies. This makes them a natural target for cybercriminals seeking high-value data. And the risk is rising.

According to a survey by Arctic Wolf and Above the Law, 39% of respondents said their firm had experienced a security breach within the past year. Alarmingly, of those breaches, 56% involved the loss of confidential client data, one of the most serious consequences a legal practice can face.

While many firms are actively investing in cyber security, the sophistication and frequency of threats continue to grow, meaning even well-prepared firms must remain vigilant.

2. Large Financial Transactions

Law firms are data-rich organisations, trusted with sensitive information ranging from confidential contracts and intellectual property to client identities and litigation strategies. This wealth of data makes them a prime target for cybercriminals. While many firms are strengthening their defences, the increasing complexity of cyber threats means even well-prepared practices can face significant challenges.

3. Low Tolerance for Public Exposure

In the legal sector, trust is paramount. A cyber attack on a law firm threatens not only data integrity but also the firm’s reputation. The UK legal industry is built on confidentiality and discretion, making any breach of client information particularly damaging.

Cybercriminals exploit this by threatening to leak stolen data unless a ransom is paid. Such tactics are effective because the potential reputational harm can be more devastating than the immediate financial loss.

The 2025 Integris Report: Law Firms, Cybersecurity and AI: What Clients Really Think highlights the gravity of this issue. According to the report, nearly 40% of clients say they would fire or consider firing their law firm after a data breach, underscoring the growing expectation for law firms to adopt airtight cybersecurity practices. Additionally, 37% of clients are willing to pay a premium for firms that emphasize cybersecurity as part of their service, marking a clear opportunity for law firms to turn IT investment into a differentiator.

These findings underscore the critical importance of robust cybersecurity measures. Law firms must not only implement strong security protocols but also communicate these efforts transparently to clients. By doing so, they can reinforce trust, meet client expectations, and differentiate themselves in a competitive market.

4. Third-Party Weaknesses

Law firms increasingly depend on a network of third-party vendors for essential services such as IT support, document management, cloud storage, and legal technology platforms. While these partnerships enhance operational efficiency, they also introduce significant cybersecurity risks.

A notable example is the 2023 cyberattack on CTS, a managed service provider for numerous UK law firms. This breach disrupted operations across multiple firms, particularly affecting conveyancing transactions, and underscored the cascading impact a single vendor compromise can have on the legal sector.

According to Risk Ledger, 62% of data breaches are linked to third-party suppliers, highlighting the critical need for robust third-party risk management (TPRM) strategies.

What are common Cyber Attacks targeting UK Law Firms?

UK law firms are facing a growing array of cyber threats, ranging from fast-moving ransomware to stealthy espionage-style breaches. Each type of attack presents unique risks to client confidentiality, business continuity, and regulatory compliance. Below, we break down the most critical threats and how they typically unfold within the legal environment.

Ransomware Attacks.

Ransomware continues to be one of the most disruptive and financially damaging forms of cyber-attack affecting law firms in the UK.

In these attacks, cybercriminals gain access to a firm’s systems and encrypt critical data, rendering case files, email servers, and legal documents inaccessible. The attackers then demand a ransom, often in cryptocurrency, in exchange for the decryption key.

Modern ransomware campaigns increasingly involve double extortion: before encrypting files, the attackers exfiltrate data and threaten to leak it publicly unless additional payments are made. For law firms handling confidential or high-profile cases, this can cause irreparable reputational damage, regulatory penalties, and legal liabilities.

Adding to the complexity, some attackers are now using “harvest now, decrypt later” tactics. This tactic was explored in our PKI webinar with Sectigo and involves stealing and storing encrypted data today with the intention of decrypting it in the future as cryptographic protections evolve or weaken. This is especially concerning for firms managing sensitive or long-duration cases, where confidentiality needs to be preserved for years.

Why it matters for law firms:

• Ransomware can bring all operations to a standstill.
• Case deadlines and court filings may be missed.
• Leaked data may compromise client outcomes or violate GDPR.

Phishing and Business Email Compromise (BEC).

Phishing is the most common entry point for cyber attacks in the legal sector. It involves deceptive emails crafted to trick recipients into clicking malicious links, downloading infected attachments, or entering login credentials on fake login pages.

Business Email Compromise (BEC) is a targeted subtype of phishing where attackers impersonate partners, clients, or financial institutions to manipulate staff into making unauthorised transactions or disclosing sensitive information.

These attacks often exploit the fast-paced, detail-heavy nature of legal work. A single fraudulent email appearing to come from a known client can lead to a six-figure payment being redirected to a criminal-controlled account.

Key risks for firms:

• Loss of client funds or firm assets.
• Exposure of sensitive case information.
• Damage to client trust and brand reputation.

Insider Threats.

Not all risks come from outside the firm. Insider threats, caused by employees, contractors, or even former staff, can be just as dangerous.

Some are malicious insiders, such as disgruntled staff deliberately leaking or deleting files. More commonly, threats stem from negligence, such as:

• Forwarding confidential documents to personal email.
• Using weak passwords or unsecured personal devices.
• Falling victim to social engineering.

Why it’s critical:

• Insider threats are hard to detect with perimeter defences.
• Legal firms must balance security with trust and collaboration among staff.
• Regulatory penalties apply regardless of whether a breach is caused by error or malice.

Advanced Persistent Threats (APTs).

APTs are highly sophisticated, prolonged cyber attacks—typically conducted by well-resourced cybercriminals or nation-state actors.

Unlike quick-hit ransomware or phishing campaigns, APTs involve months of stealthy activity. The attacker gains initial access (often through a compromised email or vendor) and then slowly moves through the network, escalating privileges and extracting data over time.

Law firms engaged in:

• High-value litigation,
• Cross-border transactions, or
• Government-related cases

…are particularly at risk of being targeted for economic espionage or politically motivated data theft.

Why APTs are dangerous:

• The reputational and legal fallout may only appear long after the attacker has gone.
• They often go undetected for months.
• The breach can span dozens of clients and case types.

Final Thoughts: Cyber Resilience Starts Now.

Cyber attacks on UK law firms are increasing in frequency, sophistication, and impact. This isn’t a future concern, it’s a clear and present risk. Legal practices that treat cybersecurity as a strategic business imperative, rather than just an IT responsibility, will be best positioned to protect their clients, preserve their reputation, and build long-term operational resilience.

But as threat actors evolve, so do the tools available to defend against them, and few technologies are reshaping the security landscape as rapidly as artificial intelligence.

Our next post explores how AI is both a weapon and a shield in modern cybercrime: how attackers are using it to enhance their tactics, and how law firms can harness it to stay one step ahead.

At Secon, we work with law firms across the UK to strengthen their defences, respond to emerging threats, and build cyber resilience that lasts.