Microsoft 365 permissions often grow silently. One user shares a folder in SharePoint, another creates a team in Teams, someone invites an external collaborator, access links are generated and, little by little, the company loses clarity over who can view, edit or download certain information.
The problem does not usually appear on day one. Microsoft 365 makes collaboration easier, and that is positive. The risk arises when this collaboration is not supported by structured, reviewed permissions management aligned with the real needs of the business.
In many companies, SharePoint and Teams have become the main repository for documentation: contracts, commercial proposals, customer data, internal documentation, financial information, procedures, projects and files shared with suppliers. If permissions are not properly defined, the risk is not only technical. It also affects confidentiality, regulatory compliance and operational continuity.
In this article, we explain why permissions management in SharePoint and Teams should be treated as a systems and cybersecurity priority, which mistakes are most common and how a company can regain control before disorder becomes a security breach.
Microsoft 365 permissions: collaboration yes, lack of control no
Microsoft 365 is designed to help teams work in an agile way. SharePoint allows companies to manage documents and internal sites. Teams centralises conversations, meetings, channels and files. OneDrive supports individual work and occasional information sharing.
But this flexibility also involves responsibility. Every site, library, folder, channel, team, shared link or guest user can modify the real access map to company information.
Microsoft distinguishes between different permission models in SharePoint, such as owners, members and visitors, and allows access to be assigned through individual users, security groups or Microsoft 365 groups. In sites connected to Teams, permissions management may depend on the Microsoft 365 group associated with the team.
This means that an apparently simple change, such as adding a user to a Teams team, can give that user access to files stored in SharePoint. And, if there is no clear policy, the company may end up with duplicated, inherited or directly assigned permissions granted to people who should no longer access that information.
Why SharePoint and Teams become disorganised so easily
Permissions chaos in Microsoft 365 is not usually the result of one single bad decision. It normally appears through the accumulation of small everyday actions that no one reviews globally.
Some common situations include:
- Teams created without a clear naming convention or responsible owners.
- Private channels used to separate sensitive information without reviewing their members.
- SharePoint folders with unique permissions that break site inheritance.
- Guest users who still have access after a project has ended.
- Shared links circulating by email, chat or meetings without later control.
- Team owners who change department or leave the company.
- Security groups that are poorly maintained or reused for different purposes.
The result is a false sense of order. The company believes its documents are protected because they are inside Microsoft 365, but in reality, it does not know precisely who has effective access to each resource.
Shared links: one of the most sensitive points
One of the most sensitive elements in SharePoint permissions management is shared links. Microsoft distinguishes between several types of links, such as anyone links, links for people in the organisation and links for specific people. Each one has different implications for security and traceability.
“Anyone” links are especially sensitive because they allow anyone with the link to access the content, without needing to authenticate. Microsoft describes them as transferable and revocable links, but warns that access through this type of link cannot be audited in the same way as authenticated access.
In a business, this can become a problem when documents are shared with customers, suppliers or external collaborators without setting an expiry date, without restricting download or without later checking whether that link is still active.
For this reason, a secure policy should not be limited to “allowing or blocking sharing”. It should define what type of links can be used, on which sites, with which users, for how long and under what conditions.
Guest users in Teams: necessary, but controlled
Guest access in Teams is very useful for working with customers, suppliers or partners. It allows collaboration in teams, channels, documents, chats and applications without having to create a full internal account for each external collaborator.
Microsoft states that, when an external user is invited to Teams, a guest account is created in Microsoft Entra ID, and that user is covered by Microsoft 365 compliance and audit mechanisms. Policies such as conditional access or multifactor authentication can also be applied to B2B users.
The problem appears when these guests remain indefinitely. A supplier who took part in a project a year ago, an external consultant who no longer works with the company or a customer who only needed temporary access may still appear in teams, groups or sites if no one reviews their lifecycle.
External collaboration must be managed with a start date, objective, internal owner and periodic review. It is not enough to invite users: the company must know when they no longer need access.
Unique permissions in SharePoint: when the structure stops being understandable
SharePoint allows companies to break permission inheritance and assign specific access to libraries, folders or files. This functionality can be useful in specific scenarios, but overusing it creates environments that are difficult to administer.
When every folder has different permissions, the IT team loses visibility. Reviewing who accesses what is no longer simple. In addition, any organisational change requires multiple permission levels to be reviewed, with the risk of leaving residual access in place.
Microsoft sets limits for unique permissions in SharePoint lists or libraries. Although the supported limit is high, the general recommendation is not to exceed 5,000 unique permissions per list or library, precisely to avoid management and performance issues.
In practice, a company should not wait until it approaches those limits. If a document library needs too many exceptions, the problem is probably not in SharePoint, but in the design of the information structure.
Real risks of poor Microsoft 365 permissions management
Poor permissions management does not always cause a service outage. That is why it often goes unnoticed. However, it can open the door to significant risks for the business.
- Leakage of sensitive information: internal documents accessible to people who should not see them.
- Exposure of personal data: risk of GDPR non-compliance if customer, employee or supplier data is shared without control.
- Loss of commercial confidentiality: offers, margins, contracts or strategies available to unauthorised profiles.
- Residual access: former employees, guests or suppliers with active permissions.
- Audit difficulty: inability to respond quickly to the question “who has had access to this document?”.
- Greater impact in the event of a compromised account: if a user has more permissions than necessary, an attack on that account may affect more information.
In cybersecurity, the principle of least privilege is key: each user should only have the permissions needed to do their job. In Microsoft 365, this means reviewing not only licences or active accounts, but also sites, teams, groups, links and guests.
How to regain control of permissions in SharePoint and Teams
Microsoft 365 permissions management should not be approached as a one-off clean-up. It should become an ongoing governance process, with clear owners and regular reviews.
1. Inventory sites, teams and owners
The first step is to know what exists. Many companies have duplicated Teams teams, old SharePoint sites, spaces created for completed projects or owners who are no longer in the organisation.
It is advisable to create an inventory with:
- Team or site name.
- Associated department or project.
- Functional owner.
- Technical owner.
- Type of information stored.
- Internal users with access.
- External or guest users.
- Information sensitivity level.
2. Review guests and external access
Guests should be reviewed with special attention. Not all external access is a risk, but every external access should have a justification.
It is advisable to check which guests exist, which teams they belong to, when they were created, who invited them and whether they still have a real need for access.
3. Limit shared links
Shared links should be configured according to the sensitivity level of the information. In many business environments, links for specific people should be prioritised over broad or anonymous links.
It is also advisable to apply expiry dates, restrict download where appropriate and prevent users from sharing externally from sites that contain critical information.
4. Avoid individual permissions whenever possible
Assigning permissions directly to specific users may seem quick, but it complicates administration. Whenever possible, it is better to work with well-defined groups: management, administration, sales, operations, support, projects or customer-specific groups.
This makes onboarding, offboarding, department changes and regular reviews easier. It also reduces errors when a person changes role within the company.
5. Enable auditing and review activity
Microsoft Purview allows companies to consult activities recorded in the Microsoft 365 audit log, including user and administrator activity in Teams and other services. Microsoft states that audit logging is turned on by default in Microsoft 365 organisations, unless a warning appears indicating otherwise.
Auditing does not replace a good permissions policy, but it helps investigate access, changes, sharing and anomalous behaviour. To be useful, it must be part of a review process, not something that is only consulted when an incident has already occurred.
Best practices for a Microsoft 365 permissions policy
An effective permissions policy must be understandable for users and administrators. If it is too complex, no one will apply it correctly. If it is too permissive, it will leave security gaps.
These best practices help establish a solid foundation:
- Define a clear naming convention for teams, sites and groups.
- Always assign at least two responsible owners per team or site.
- Prevent any user from creating teams without control if the company requires centralised governance.
- Classify information according to sensitivity: internal public, confidential, critical or regulated.
- Configure differentiated policies for internal sites, customer projects and sensitive documentation.
- Review guest users periodically.
- Remove access when a project or contractual relationship ends.
- Document who can approve special permissions.
- Audit relevant changes in permissions and sharing.
- Train users on the correct use of shared links.
Technology provides the tools, but real control comes when configuration, procedure and monitoring are combined.
How Inmove IT Solutions can help
At Inmove IT Solutions, we help companies review, organise and protect their Microsoft 365 environments from a practical perspective: security, continuity, productivity and compliance.
A permissions review may include the analysis of SharePoint, Teams, OneDrive, Microsoft 365 groups, guest users, shared links, external access policies and audit configuration. The aim is not to block collaboration, but to ensure that each user accesses only what they need.
This type of work fits especially well within an IT systems audit, where the real status of the technology environment is reviewed and areas for improvement are identified.
It is also directly related to data protection and GDPR compliance, as poor permissions management can expose personal or confidential information without the company being aware of it.
And, from a global security perspective, it should be complemented with perimeter security for businesses, identity control, multifactor authentication, monitoring and well-defined access policies.
Conclusion: permissions are also cybersecurity
Microsoft 365 security does not depend only on strong passwords, antivirus or firewalls. It also depends on something much more everyday: who can access each document, from where, for how long and with what permission level.
SharePoint and Teams are very powerful tools for improving business collaboration, but they need governance. Without proper management, permissions accumulate, guests remain, links are forgotten and the company loses visibility over its own information.
Reviewing Microsoft 365 permissions is not a minor administrative task. It is a security, compliance and operational control measure.
If your company uses SharePoint, Teams or OneDrive and is not clear about who accesses which information, at Inmove IT Solutions we can help you review the environment, organise permissions and establish a secure and sustainable access policy.
For anything you need, contact us and we will help you assess the current status of your Microsoft 365 environment with a technical, practical and business-oriented approach.
Frequently asked questions about Microsoft 365 permissions
Why is it important to review permissions in SharePoint and Teams?
Because SharePoint and Teams concentrate a large part of business documentation. If permissions are not reviewed, active access may remain for users who no longer need it, external guests, former employees or people from other departments.
What is the difference between permissions in Teams and permissions in SharePoint?
Teams uses SharePoint to store team and channel files. Therefore, adding a user to a Teams team may give that person access to documents stored in the associated SharePoint site. Management should be reviewed jointly.
Is it dangerous to share files using links?
Not always, but it depends on the type of link. Links for specific people offer more control than broad or anonymous links. For sensitive documentation, it is advisable to restrict the type of link, apply expiry dates and periodically review shared access.
How often should guest user access be reviewed?
It depends on the level of external collaboration, but it should at least be reviewed periodically and always when projects, contracts or supplier relationships end. Guests should not remain indefinitely without justification.
Does a permissions audit help with GDPR compliance?
Yes. A permissions audit helps detect excessive or inappropriate access to personal or confidential information. This helps reduce data exposure risks and strengthen the organisational and technical measures required by the GDPR.
