The Hidden Attack Surface: How Shared Drives Undermine Enterprise Security (and What You Can Do About It)

Every organisation has one. That shared drive that’s been around for years, filled with project folders, spreadsheets, meeting notes, contracts and documents that have gradually accumulated over time. People know roughly where things are, new folders are added whenever a project begins, and everyone gets on with their work without giving it much thought. 

That’s exactly why shared drives can become such an overlooked security risk. They exist to make collaboration easier, and for the most part they do exactly that. The challenge is that, as organisations grow and change, shared drives rarely stay as organised as they once were. Permissions are added to help people do their jobs, folders are shared across departments, contractors are given temporary access, and new teams inherit files from old projects. 

Months or years later, very few people have a complete picture of who can access what. 

What Is a Hidden Attack Surface? 

When security professionals talk about an attack surface, they’re referring to every possible route a cyber attacker could use to gain access to systems or sensitive information. 

Most people immediately think about phishing emails, vulnerable software, cloud services or stolen passwords. Those are all important, but they’re only part of the picture. 

Shared drives create another type of attack surface that’s much easier to overlook. 

Every folder, every document and every permission creates another opportunity for an attacker if they manage to compromise an account that already has permission to view those resources. Once they’re inside the organisation, they don’t have to break through every security control individually. Instead, they inherit whatever access that employee already has. 

That’s why compromised accounts remain such a significant risk. IBM’s Cost of a Data Breach Report found that stolen or compromised credentials were the most common initial attack vector globally, accounting for 16% of breaches, with those incidents also taking the longest to identify and contain.  

If permissions have gradually expanded over time, that can give attackers access to far more information than anyone intended. 

How Shared Drives Become Security Risks 

Shared drives don’t suddenly become insecure overnight; the risk usually builds slowly through hundreds of perfectly reasonable decisions. 

Businesses evolve constantly. New employees join, teams merge, contractors need temporary access, projects are created and archived, and people move into new roles. Every one of those changes is likely to involve someone granting access to another folder or sharing another set of files so work can continue smoothly. 

The problem is that access is much more likely to be granted than removed. Over time, all those small decisions start to accumulate. Information that was originally intended for a handful of people gradually becomes available to dozens more, and files that are no longer needed often stay exactly where they are. 

Nobody notices because nothing appears to be wrong. Employees can still find the information they need, projects continue moving forward and the shared drive just becomes part of everyday working life. 

It’s often only after a security incident that organisations discover how widely sensitive information had been shared. 

Why Shared Drives Appeal to Attackers 

Shared drives often contain exactly the information attackers hope to find once they’ve gained access to an organisation. 

Customer records, supplier contracts, financial reports, HR documents, organisational charts and commercially sensitive plans all help cybercriminals understand how a business operates. Even documents that don’t appear particularly valuable on their own can reveal useful details about systems, suppliers, internal processes or key individuals. 

That information allows them to build a much clearer picture of the organisation they’re targeting. It can help them identify high-value systems, create more convincing phishing emails, impersonate trusted colleagues or prepare for a much larger attack later on. The longer they remain unnoticed, the more information they can gather and the easier those next steps become. 

Everyday Decisions Have Security Consequences 

It’s easy to assume this is purely an IT problem, but shared drive security is influenced by everyday decisions made across the organisation. 

Employees save files where they’re easiest to find, documents get copied into shared folders so colleagues can access them quickly, and access requests are approved because somebody needs information urgently to finish a piece of work. 

None of these decisions are unusual, and they’re certainly not malicious. They’re just the kinds of shortcuts people take when they’re busy and trying to help each other. Over time, though, those small decisions gradually increase the amount of information that’s available if an attacker manages to compromise just one account. 

That’s why shared drive security is as much about behaviour as it is about technology. 

Making the Invisible Visible 

One of the biggest challenges with shared drives is that the risk isn’t always visible. 

Employees rarely know who else can see the folders they’re using or understand how widely a document might be accessible once it’s been saved. From their perspective, they’re just storing information so other people can work with it. 

That’s why security awareness needs to go beyond phishing emails and password security. People need to understand how everyday decisions affect the organisation’s wider security posture. Knowing where sensitive information should be stored, thinking carefully before granting access, and recognising when information no longer needs to be shared are all behaviours that reduce security risk long before an attacker has an opportunity to exploit it. 

Bringing Hidden Risks to Life 

One of the reasons these risks are difficult to explain is that they don’t always feel particularly dramatic. 

A folder being shared with too many people doesn’t immediately feel like a cyber security incident. Neither does saving a document in the wrong location or approving an access request without questioning it. 

The consequences usually appear much later. 

That’s why Cyber Police takes a different approach. MetaCompliance’s live-action cyber awareness video series uses realistic workplace stories to show how seemingly ordinary decisions can create opportunities for attackers. Using professional actors and dramatised scenarios, it explores how modern cyber threats develop, how employees become part of the story, and how small moments like file sharing can have much bigger consequences than anyone expected. 

When people see these situations unfold in realistic settings, it’s much easier to recognise similar risks in their own working environment. 

Reducing Your Hidden Attack Surface 

Shared drives will always play an important role in collaboration, and the goal of securing them isn’t to lock everything down or make information difficult to access. 

Instead, organisations need to make sure access reflects how the business operates today rather than how it looked several years ago. 

Regular permission reviews, clear ownership of sensitive information, sensible file management and good governance all make a significant difference. Just as importantly, employees need to understand why these processes exist and how their own decisions contribute to the organisation’s overall security. 

When technology, governance and awareness work properly together, shared drives become far less attractive to attackers. 

Security Is About More Than the Front Door 

Many organisations invest heavily in preventing attackers from getting inside their network. That’s essential, but it’s equally important to think about what an attacker would find if they succeeded. 

Shared drives often contain years of valuable business information, and without the right controls they can become one of the largest hidden attack surfaces in the organisation. 

The businesses that manage this risk most effectively recognise that cyber security doesn’t stop at the perimeter. It continues inside the organisation through good governance, sensible access controls and employees who understand how everyday decisions help protect sensitive information. 

Find Out More About Cyber Police 

Cyber Police uses drama to bring real cyber threats to life, sparking conversation and challenging assumptions on what we know about cyber attacks today. 

Each season tackles the attacks employees are most likely to face, from phishing and ransomware to deepfakes, and reimagines them as gripping episodes. 

By seeing threats through the eyes of those affected, employees gain clearer awareness and the confidence to respond effectively. 

Find out more about Cyber Police and see how story-driven security awareness training helps employees recognise and respond to modern cyber threats with confidence. You can also watch a free episode to see the series in action, or speak to our team about how Cyber Police can help strengthen your organisation’s security culture.