Microsoft 365 has turn into the central nervous system of recent enterprise — and cybercriminals realize it. Simply as Home windows turned the first goal for attackers due to its market dominance within the Nineties and 2000s,
Microsoft 365 now finds itself within the crosshairs for having “received” the e-mail and collaboration struggle.
With over 400 million paid Workplace 365 seats worldwide and numerous organizations counting on its built-in suite of purposes, Microsoft 365 represents the final word target-rich surroundings for risk actors.
The winner’s curse: Success breeds danger
The parallel between Home windows’ safety journey and Microsoft 365’s present predicament is hanging. Home windows has turn into a primary goal of assaults throughout the working methods market not as a result of it was inherently much less safe than options, however as a result of attacking Home windows meant accessing the most important attainable pool of potential victims.
As we speak, Microsoft 365 faces the identical winner’s curse. Having efficiently consolidated electronic mail, file sharing, collaboration and communication right into a single ecosystem, Microsoft 365 has painted a large goal on its again.
This dominance creates a multiplication impact for attackers. A single profitable marketing campaign concentrating on Microsoft 365 can probably influence thousands and thousands of customers throughout hundreds of organizations. For cybercriminals working on a cost-benefit evaluation, the maths is straightforward:
Why develop separate assault vectors for a number of platforms when you possibly can focus your efforts on the one platform that reaches essentially the most targets?
Multisurface risk vectors
Microsoft 365 presents a fancy net of interconnected providers that dramatically develop the assault floor. Every utility — Outlook, SharePoint, Groups and OneDrive — represents a possible entry level, and their tight integration means compromising one service gives pathways to others.
This creates “lateral motion alternatives.” An attacker gaining entry by phishing in Outlook can pivot to exfiltrate SharePoint knowledge, manipulate OneDrive paperwork or be a part of confidential Groups conferences.
The seamless expertise that appeals to companies turns into a dream situation for attackers looking for to maximise influence.
Current SharePoint vulnerabilities spotlight this hazard. In July 2025, Microsoft patched zero-day vulnerabilities together with CVE-2025-53770, that was actively exploited towards on-premises SharePoint clients since July 7, affecting over 75 servers.
These assaults reveal cascading danger, the place compromising SharePoint gives entry to all the collaborative infrastructure.
Acronis Cyber Defend Cloud integrates knowledge safety, cybersecurity, and endpoint administration.
Simply scale cyber safety providers from a single platform – whereas effectively operating your MSP enterprise.
Hidden in plain sight: The backup blind spot
Probably the most neglected dangers in Microsoft 365 environments lies in backup and restoration methods. Many organizations assume that Microsoft’s built-in retention insurance policies and model historical past present ample safety, however this creates harmful blind spots.
Normal Microsoft 365 backups typically lack the granular restoration choices wanted to reply to refined assaults, and worse, they will truly retailer and protect malicious content material that turns into a future assault vector.
When scanning URLs in Microsoft 365 electronic mail backups, analysts found that 40% contained phishing hyperlinks that had been dutifully preserved alongside reputable enterprise communications.
Much more alarming, over 200,000 backed-up emails contained malware attachments. These findings expose a crucial flaw in conventional backup approaches: Organizations should not simply storing their knowledge — they’re creating everlasting archives of the very threats designed to destroy them.
Which means restoring from backup after a safety incident might probably reintroduce the unique assault vectors again into the surroundings. When ransomware actors encrypt SharePoint libraries or corrupt Trade mailboxes, having sturdy, remoted backups turns into the distinction between a fast restoration and a business-ending disaster.
But many MSPs and IT groups uncover too late that their backup methods have crucial gaps when dealing with trendy threats that particularly goal cloud collaboration platforms.
Hardening with out hampering
MSPs and IT groups should implement sturdy safety controls with out undermining Microsoft 365’s productiveness advantages. This requires layered defenses past native safety features.
Zero belief structure turns into important, with steady verification of person identities and system well being. Multifactor authentication must be non-negotiable however carried out to keep away from person friction that drives workarounds.
Superior risk safety should lengthen throughout all Microsoft 365 purposes — from SharePoint doc scanning to Groups monitoring and OneDrive habits evaluation. Safety groups want cross-application visibility to detect anomalous entry patterns.
Common assessments ought to give attention to Microsoft 365 configurations, together with Energy Platform permissions, third-party integrations and visitor entry controls. The ecosystem’s complexity means misconfigurations can create persistent safety gaps.
The trail ahead
Microsoft 365’s dominance makes it an inevitable goal. Organizations should acknowledge that securing it requires specialised experience and instruments tailor-made to cloud collaboration threats.
The purpose is not to desert Microsoft 365 — its advantages are too vital. As an alternative, organizations should acknowledge elevated dangers and implement proportionate measures, treating Microsoft 365 safety as a specialised self-discipline, not a checkbox merchandise.
Organizations that proactively harden defenses preserve a aggressive benefit whereas defending delicate property. People who do not study the exhausting approach why being the most important goal brings the most important dangers.
About TRU
The Acronis Risk Analysis Unit (TRU) is a group of cybersecurity consultants specializing in risk intelligence, AI and danger administration.
The TRU group researches rising threats, gives safety insights, and helps IT groups with tips, incident response and academic workshops.
See the most recent TRU analysis.
Sponsored and written by Acronis.
