Microsoft Office 365 security best practices for business

Office 365 security best practices cover

Office 365 is a popular business platform worldwide. Its blend of collaboration tools, office apps, and cloud storage components makes Office 365 a go-to option for many companies. But the popularity of Office also makes it a popular target for cyber-attackers.

Securing data and protecting assets is critically important when using Office 365. This blog will discuss the major threats faced by users and we will suggest some security best practices. Office 365 is a safe place to run business operations. But you need awareness and policies to make that safety a reality.

How secure is Office 365?

Office 365 is a suite of cloud-based business tools. Like all cloud applications and platforms, Office is vulnerable to external attackers. Cyber-attackers can breach user defenses. They can access sensitive data, disrupt operations, and cause plenty of damage before they are stopped.

Security concerns are real. Up to 85% of organizations using Office 365 suffered an email data loss in 2021. 15% of organizations using the platform suffered more than 500 breaches in the same year. Just 4% of organizations not using Office 365 reported the same data breach frequency.

Microsoft has toughened Office security features in the past few years. However, Office 365 users still need to control their security posture. If you can find a secure configuration that meets your needs, you can use the platform safely. The first step in doing so is mastering the security features supplied by Microsoft.

Security features in Office 365

Users can access most Office 365 security features via the Security and Compliance Center on Microsoft Accounts. This cloud-based portal allows users to choose several critical security functions. These functions include:

1. Identity and Access Management (IAM)

Microsoft’s IAM solution lets you set up digital identities for all Office users.

Every user has a digital identity containing their authentication details and authorization information. This lets administrators add adaptive multi-factor authentication for all log-ins. Admins can manage passwords efficiently, onboard and remove users as needed.

IAM also allows you to manage authorization options for all users. Admins can set privileges based on roles or individual requirements. This limits app access to users with appropriate permissions. Unauthorized outsiders won’t be able to intrude.

2. Information security

With Microsoft Information Protection (MIP), users can manage data as it travels across Office cloud resources and even on remote work devices.

Users can classify data to ensure it only reaches authorized devices. Set different sensitivity levels to make data available or defend it as required.

Classification works alongside Data Loss Prevention (DLP) and Microsoft Information Governance (MIG) tools. Create robust security controls for confidential data, and set lifecycle controls to delete data when it is not needed.

3. Threat defenses

Microsoft offers Office-native Security Information and Event Management (SIEM) and Extended Detection and Response (XDR) features. Together, they neutralize cyber threats and track traffic to assess security weaknesses.

Microsoft Sentinel is a SIEM system that uses Artificial Intelligence to monitor the Office environment. Sentinel can track every active Office application and device. Security teams benefit from real-time visibility across the threat surface.

Microsoft Defender and Office 365 Defender are XDR tools. They extend threat detection to all endpoints, including email accounts and cloud applications.

4. Risk management

Office 365 includes a suite of tools to manage risks and ensure compliance. These tools identify and classify risks, focusing on data protection across an Office 365 environment.

Risk management tools allow security teams to assess insider threats, manage the risk of insecure communications, and fine-tune privileges for admin accounts. Audit tools let you drill down into compliance issues until every data security weakness is covered.

What are the most important Office 365 security concerns?

The security tools above are comprehensive and flexible. But they are generally voluntary. Users need to create their own security setup and choose measures that fit their Office implementation.

Office 365 leaves plenty of room for misconfigurations. And these gaps are the ideal space for attackers to work. Here are some critical threats for security managers to assess:

1. Credential theft and unauthorized access

Cyber attackers may gain access to your entire Office 365 environment if they steal user credentials. Users can leak credentials in many ways. For instance, employees could:

  • Share information insecurely via Office collaboration apps

  • Click on attachments that extract personal data

  • Follow unsafe links in social engineering email messages

  • Install malware onto a connected device

Credential theft is a constant security concern for Office 365 managers. Office does include multi-factor authentication, but MFA is not enabled as a default. Many companies forget to apply extra authentication and suffer as a result.

2. Unsafe privileges

According to Zero Trust principles, Office 365 users should have access to the resources they need and nothing more. Limiting access to sensitive data makes data extraction and loss less likely. Hackers cannot freely access data. Employees won’t be able to leak data during their tasks accidentally.

However, privileges creep can lead to too many people having access to too much data. By default, every Global Administrator Account has extensive privileges. Security teams need to restrict admin accounts manually. This potentially leaves scope to abuse access and steal data.

3. Data loss

Data breaches are a nightmare scenario for Office 365 managers, but they are possible without adequate security controls.

The major problem here is sharing. Office is built to enable information exchange. Workers share documents, conversations, databases, and much more. This is great at an operational level. But the flow of data is a security problem.

Data can leak via many storage locations or sharing tools. Employees may not know about data sharing risks or how to store data securely. And data can pass to unauthorized third parties without the knowledge of security teams.

4. Complacency

Many companies move from on-premises Office implementations to cloud-based 365 environments. While the applications are familiar, the security context of these two setups is very different.

Security managers may lack visibility of all cloud endpoints and in-use applications. They may lose sight of data containers or fail to turn on necessary security features. Sharing tools like SharePoint present new risks, such as allowing access for third-party guests. But these new risks aren’t always detected during cloud transitions.

Office 365 security best practices for business

the best practices for using microsoft office 365 for business

What can businesses do about the security threats listed above? The answer lies in applying Office 365 security best practices. By following these security practices, you can enjoy the benefits of information sharing and keeping data safe.

1. Enable IAM

Access management is the top priority when securing Office 365 environments. Companies must create a secure perimeter and restrict access for unauthenticated users. Users should have the privileges they need to carry out work, but no more access than they require.

Office 365 has built-in IAM tools to control authentication and authorization centrally. Set conditional access policies for every role and back up password access with MFA technologies. Bring all Office 365 apps together via Single Sign On (SSO). This makes it easier for employees to manage passwords. It also simplifies access management for security professionals.

It is advisable to create separate user accounts for admins with elevated privileges. Every admin account requires maximum protection. Users should only use administrative accounts for specialist tasks, and rely on other accounts for everyday work.

2. Educate users to understand Office 365 security

Employees must know how to avoid phishing attacks. Build anti-phishing training into all onboarding processes and refresh this knowledge regularly. Workers should always be aware of dangerous email attachments and how to spot malicious links.

Users also require training in how to share information securely. Educate staff on how to use SharePoint and Teams without compromising security.

3. Collaborate securely

Education combines with robust collaboration app security to protect data in-transit. Install DLP systems to track sensitive files and ensure they stay within the network perimeter. DLP will alert managers if employees share critical data, and block any illegitimate transfers.

Set up Message Encryption on Teams and other communication tools. This protects the content of messages. Only authorized users will be able to read messages or open files.

Use Safe Attachments to scan all email attachments and shared files. Extend attachment protection to Teams, SharePoint and OneDrive so that all potential endpoints enjoy security coverage.

4. Put in place anti-phishing protections

Office 365 includes specialist tools to handle phishing attacks. These advanced threat protection tools go beyond trusting employees not to open malicious links. They actively inspect emails to detect malicious content.

For example, users can sandbox attachments automatically with Application Guard. This creates a protected environment to open pdfs or spreadsheets. Application Guard scans files to detect unsafe sources. This matters because Office files are common attack vectors. Sandboxing makes it much less likely that an innocent document will spark a security alert.

Safe Links is another useful anti-phishing tool that scans URLs to detect security concerns. And you can set “external” email tagging for inbound messages. This alerts users to be careful when opening external communications.

These measures do not remove all phishing risks. Zero-day threats are still an issue. But together, Application Guard, email tagging and Safe Links provide plenty of defense against social engineering attacks.

5. Use anti-malware solutions

When anti-phishing measures fail, malware protection tools enter the picture. Office 365 users should take advantage of Microsoft’s anti-malware tools wherever possible.

Implement SIEM protection via Azure Sentinel, and use XDR to scan all endpoints. These two tools work together to detect malware infections and quarantine affected files. This should neutralize ransomware attacks before they take down network infrastructure.

6. Strengthen your password policies

User access is the major Office 365 security weak point. And credential theft is the most common attack vector. Make it harder to mount credential stuffing attacks by enforcing strong password policies across all users.

Make sure Office users avoid real names and familiar words. Include multiple symbols and numbers, in combinations that are impossible to anticipate. Use password manager tools to store and update passwords. This reduces the risk of human error.

Generally, make sure users do not reuse passwords from other network assets. Every Office 365 user requires unique credentials, with no exceptions.

7. Strengthen data security controls

Employ MIP to lock down sensitive information and allow access to less important data. Office 365 lets you label sensitive information such as personally identifiable information (PII) and financial records. These labels enforce tools to keep sensitive data secure, such as encryption or watermarking.

DLP also allows you to track data movements and prevent data leaving organizational boundaries. This makes it easier to work remotely without creating additional data loss risks.

8. Check compliance and security scores

Data security measures aim to meet strict compliance goals. For instance, you may need to protect financial records to comply with PCI-DSS, or meet HIPAA rules when handling patient details. Microsoft has created tools to make the compliance task easier, so use them when available.

The Office 365 compliance portal provides guidance for meeting important regulations. It also includes a compliance score that charts your progress. Updated in real-time, the compliance score suggests required actions. It provides a useful road map to compliance across all Office 365 services.

Office also provides an overall Secure Score. This can be found in the Security Center, which records a percentage based on an organization's security posture. Adding extra security measures boosts the score, and the system delivers recommendations based on your Office 365 setup.

9. Optimize mobile device security

Employees may use mobile devices to access Microsoft's SaaS applications. This particularly applies to companies with large communities of remote workers or BYOD setups. In any case, it is advisable to implement Mobile Device Management (MDM) security solutions,

Office 365’s MDM tools encrypt confidential data on mobile devices. They can wipe data from devices in the event of theft. And they prevent network access for stolen or compromised devices.

10. Put in place rock-solid Office auditing

Be sure to enable the Unified Audit Log via the Office 365 Security Center. The UAL lets you track user activity across all accounts. You can see who is sharing information and how that information spreads across your cloud environment.

By default, audit logs provide 90 days of historical information, which isn’t that much. However, you can extend the scope of audit logging to as long as ten years if desired. Longer periods provide a better evidence base for compliance management, but you will need measures to efficiently store and search audit data.

Ensure secure access to Office 365 with NordLayer

Collaborate, strategize, and store data safely with our office 365 security best practices. On-board security tools and solid staff education let you use Microsoft’s business environment without creating unnecessary risks.

However, just relying on Office 365 controls is a risky move. That’s especially true for companies with hybrid cloud environments who manage multiple platforms and require secure access to SaaS apps. In those cases, it makes sense to apply enterprise-wide security solutions like NordLayer.

NordLayer’s IP allowlisting tools supplement Office 365 security controls. Admins can define a list of authorized addresses. These IP addresses are then permitted access to Office resources. Unlisted devices are excluded or require additional verification.

NordLayer encrypts traffic passing between employee devices and Office 365, countering man-in-the-middle style attacks. Threatblock also blocks malicious websites, reducing the risks posed by phishing attacks. Use Microsoft’s internal features to secure Office 365. But go further, integrating Office into your wider cybersecurity setup. To find out more, contact the NordLayer team today.

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