Office 365 is a popular business platform worldwide. Its blend of collaboration tools, office apps, and cloud storage components makes it a go-to option for many companies. However, 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 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. Cyberattackers can breach user defenses, 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. You can use the platform safely if you can find a secure configuration that meets your needs. The first step 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, so 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. It allows you to 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 an SIEM system that uses Artificial Intelligence to monitor the Office environment. Sentinel can track every active Office application and device, enabling security teams to 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.
Office 365 security best practices 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 sharing 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 can 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. You can also set “external” email tagging for inbound messages, which 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, users shouldn't t 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 from 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 compliance tasks easier so users can use them when they are 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 and 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 also wipe data from devices in the event of theft and 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 store and search audit data efficiently.
11. Zero Trust and the principle of the Least Privilege
Zero Trust is an IT framework that focuses on user and device authentication and authorization. It identifies who or what is trying to access the system and detects suspicious activity. Since authentication is needed whenever someone tries to access the system, it ensures “zero” trust.
The Principle of Least Privilege (POLP) builds on this by limiting access to only what users need. This reduces the risk of damage if an account is compromised or if a user acts maliciously. In Microsoft 365, you can implement Zero Trust and POLP by setting up user permissions, restrictions, and role-based access controls.
12. Add another layer of security with MFA
MFA secures user logins by adding extra authentication methods, making it more secure than just using passwords, even complex ones. It's always smart to have more than one way to authenticate on any platform.
You can enable MFA in Azure Active Directory for individual users by enabling Security Defaults or through Conditional Access policies. Options for MFA include using the Microsoft Authenticator app, receiving a code via text message, or using OATH hardware tokens. For OATH tokens, you'll need an Azure Active Directory Premium P1 or P2 license for each user assigned a token.
13. Make passwords stronger and safer
One of the key policies to enforce is using strong passwords. You can boost password security by setting rules for longer, more complex passwords, including numbers, special characters, and both uppercase and lowercase letters. This makes passwords harder for attackers to guess.
Tools like Microsoft’s Azure Active Directory Password Protection can also help reduce the risks of weak passwords. Regular password changes and restrictions on the reuse of old passwords are important to prevent vulnerabilities from password reuse.
It's important to balance security and user convenience to avoid frustration and complaints. Combining these password practices with other measures like multi-factor authentication (MFA) can allow for less frequent password changes without compromising security.
14. Limit admin access for better security
Only give admin access to what's needed for each role in your organization. Avoid giving the global administrator role to everyone managing your Office 365 tenant. Ideally, you should have fewer than five global admins. This follows the principle of least access, allowing users to perform only their job functions. For example, if an admin supports only Exchange, assign them the Exchange Administrator role.
Conduct access reviews for users with Azure AD roles. If someone isn’t using their access, remove it. You’ll need an Azure AD Premium P2 or E5 license to use Identity Governance in Azure AD for these reviews.
Use generic accounts when setting up configurations in Office 365. Avoid using an employee’s username, which can lead to problems if they leave the company.
15. Protect sensitive data with DLP policies
Data loss prevention (DLP) policies in Microsoft 365 help prevent sensitive information from leaving your organization. These policies use pattern matching and other methods to identify and protect financial data, personally identifiable information (PII), and other sensitive data.
To enable DLP policies, go to the Microsoft 365 Compliance Center and select ‘Data loss prevention’ under ‘Policies.’ You can then create custom policies to fit your organization’s needs or use a pre-built template.
When setting up DLP policies, you decide which types of sensitive information to protect, the conditions that trigger the policy, and the actions to take when the policy is matched. Actions might include notifying the user, blocking the content from being shared, or alerting administrators.
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, relying solely on Office 365 controls is risky. That’s especially true for companies with hybrid cloud environments that manage multiple platforms and require secure access to SaaS apps. In those cases, applying enterprise-wide security solutions like NordLayer makes sense.
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 and integrate Office into your wider cybersecurity setup. To find out more, contact the NordLayer team today.
