Find out more about the most common causes of data breaches and how organisations can prevent them from happening.
Over the course of the last two decades, everything has become more digitised. There’s no need to visit a bank to transfer money; medical information can be found on the NHS app; event tickets are stored on phones; and even checking in for flights can be done ahead of time. Yet, with more streamlined approaches to our everyday lives brings a greater responsibility for organisations storing data.
With all of the things we can do online now, we usually think nothing of uploading personal information to websites – we automatically trust that the organisation will take care of it. That’s where we’re all guilty of being too trusting.
Organisations are bound by strict data protection laws and regulations under the General Data Protection Regulation (GDPR) and the Data Protection Act. This means that their framework for collecting, storing and processing personal data must be robust, transparent and secure. Yet despite these obligations, data breaches continue to make headlines – affecting millions of people and costing businesses billions in fines and legal fees, not to mention reputational damage.
So, what actually causes data breaches? While the methods can vary widely, the underlying vulnerabilities often come down to a handful of recurring issues.
Common Causes of Data Breaches
Phishing Attacks
Phishing remains one of the most prevalent and effective methods used by cyber-criminals to gain unauthorised access to systems. Attackers typically impersonate trusted entities such as banks, HMRC or even internal colleagues through deceptive emails or messages designed to trick recipients into revealing login credentials or clicking malicious links. Once an employee inadvertently hands over their details, attackers can move laterally through a network, accessing sensitive customer and business data with ease.
Ransomware
Ransomware attacks have surged in recent years, targeting organisations of all sizes. In a ransomware incident, malicious software encrypts an organisation’s data, rendering it inaccessible until a ransom is paid – often in cryptocurrency due to its inability to be traced. Even when a ransom is paid, there’s no guarantee data will be restored or that it hasn’t already been copied and sold. High-profile attacks on the NHS and various local councils have demonstrated just how devastating this type of breach can be for critical services.
Weak or Compromised Passwords
Despite years of awareness campaigns, weak or reused passwords remain a significant vulnerability. When employees use easily guessable passwords or recycle the same credentials across multiple platforms, a breach on one system can quickly cascade into others. Credential stuffing – where attackers use lists of stolen username and password combinations to gain access to other services – is an increasingly automated and widespread attack approach.
Insider Threats
Not all data breaches originate from external actors. Insider threats – whether malicious or accidental – account for a considerable proportion of incidents. A disgruntled employee may deliberately exfiltrate data, or a well-meaning member of staff might inadvertently send sensitive files to the wrong recipient – as we have seen with the Ministry of Defence data breach, which exposed the details of thousands of Afghan nationals who supported British Forces against the Taliban.
Organisations must recognise that threats can come from within and implement access controls and monitoring accordingly.
Unpatched or Outdated Software
Software vulnerabilities when left unpatched can be exploited by attackers to gain entry to systems. Some high-profile breaches have been traced back to known vulnerabilities for which patches were available but never applied. Organisations that fail to maintain timely update schedules are particularly at risk. This is not a technical oversight but a resource issue, often due to understaffed IT teams struggling to keep pace with a constant stream of updates.
Third-Party and Supply Chain Vulnerabilities
Organisations frequently share data with third-party vendors, partners and cloud service providers. If any of these parties have inadequate security measures in place, they can become the weakest link in the chain. Supply chain attacks – where hackers compromise a trusted third-party provider to gain access to their clients’ systems – are growing increasingly sophisticated. Conducting thorough due diligence on external partners handling personal data is no longer optional; it is a legal obligation under GDPR.
Human Error
Sometimes the cause of a breach is as simple as a mistake. Misconfigured cloud storage buckets that inadvertently expose data to the public internet, accidental deletion of security settings or employees clicking on suspicious links without realising the danger – these are all examples of human error that can have significant consequences. Regular training, clear internal policies and a culture of security awareness are among the most effective defences against this type of vulnerability.
Why a Robust Data Framework is Non-Negotiable
The consequences of a data breach extend far beyond the immediate technical incident. Under GDPR, organisations can face fines of up to £17.5 million or 4% of the total annual worldwide turnover – whichever is higher – for the most serious violations. Beyond financial penalties, the reputational damage of a publicised breach can be lasting and, for smaller businesses, potentially catastrophic. Customers and clients who lose trust in an organisation’s ability to protect their data are unlikely to return.
This is why maintaining a robust, up-to-date data security framework is not simply a compliance exercise. It is a fundamental business responsibility. Organisations must invest in regular risk assessments, staff training, testing, and incident response planning. Encryption of sensitive data, multi-factor authentication and strict access controls should be baseline requirements, not optional extras. Equally important is a clear and practised data breach response plan, so that if the worst does happen, the organisation can act swiftly to contain the damage and fulfil its legal obligation to notify the Information Commissioner’s Office within 72 hours.
Ultimately, data security is a shared responsibility. While regulators set the framework and organisations implement the controls, individuals also have a role to play in being vigilant and informed. In a world where our personal data is a form of currency, the stakes have never been higher — and the cost of complacency has never been greater.
