When University of Iceland switched 2018 to Microsoft Cloud for emails and other services, I warned about this and I was also concerned about the Icelandic government's cybersecurity.

At that time, our university administration argued to me that Microsoft can better protect our cybersecurity than we can do on our own. However, threat actors managed in May and June 2023 to access Microsoft Exchange Online mailboxes: while they mainly attacked US and UK government email accounts (but also others, but who exactly is not disclosed), this could apply in theory also to our emails at University of Iceland (which enables requesting and intercepting password-reset emails in order to get access to any other non-Microsoft service that offers email-based password reset) and of course to the Icelandic government that relies as well on Microsoft's cloud-based services.

While at that time, my concerns were mainly framed by what whistleblower Edward Snowden's taught us, i.e. we get eavesdropped by our friends, 6 years later, the landscape has added more awareness on the Russian aggression and Chinese and North-Korean threat actors, including the possibility to cut off the the Internet sea cables connecting Iceland to the cloud service that are all outside of Iceland. (E.g. according to a traceroute the Microsoft cloud serves that University of Iceland uses are located in the UK -- meaning that if a state actor cuts the sea cables connecting Iceland, probably the whole IT of University of Iceland is cut off because all user authentication runs via Microsoft in the UK.)

Now, the United States Secretary of Homeland Security Cyber Safety Review Board published a devastating report on Microsoft's Cloud security. As US Government-level publications are in the public domain, I provide below some extensive direct quotes (highlighting added by me) from that report:

Throughout this review, the Board identified a series of Microsoft operational and strategic decisions that collectively point to a corporate culture that deprioritized both enterprise security investments and rigorous risk management.

To drive the rapid cultural change that is needed within Microsoft, the Board believes that Microsoft’s customers would benefit from its CEO and Board of Directors directly focusing on the company’s security culture and developing and sharing publicly a plan with specific timelines to make fundamental, security-focused reforms across the company and its full suite of products.

Microsoft leadership should consider directing internal Microsoft teams to deprioritize feature developments across the company’s cloud infrastructure and product suite until substantial security improvements have been made in order to preclude competition for resources.

The Board finds that this intrusion was preventable and should never have occurred. The Board also concludes that Microsoft’s security culture was inadequate and requires an overhaul.

The Board reaches this conclusion based on:
1. the cascade of Microsoft’s avoidable errors that allowed this intrusion to succeed;
2. Microsoft’s failure to detect the compromise of its cryptographic crown jewels on its own, relying instead on a customer to reach out to identify anomalies the customer had observed;
3. the Board’s assessment of security practices at other cloud service providers, which maintained security controls that Microsoft did not;
4. Microsoft’s failure to detect a compromise of an employee's laptop from a recently acquired company prior to allowing it to connect to Microsoft’s corporate network in 2021;
5. Microsoft’s decision not to correct, in a timely manner, its inaccurate public statements about this incident, including a corporate statement that Microsoft believed it had determined the likely root cause of the intrusion when in fact, it still has not; even though Microsoft acknowledged to the Board in November 2023 that its September 6, 2023 blog post about the root cause was inaccurate, it did not update that post until March 12, 2024, as the Board was concluding its review and only after the Board’s repeated questioning about Microsoft’s plans to issue a correction;
6. the Board's observation of a separate incident, disclosed by Microsoft in January 2024, the investigation of which was not in the purview of the Board’s review, which revealed a compromise that allowed a different nation-state actor to access highly-sensitive Microsoft corporate email accounts, source code repositories, and internal systems; and
7. how Microsoft’s ubiquitous and critical products, which underpin essential services that support national security, the foundations of our economy, and public health and safety, require the company to demonstrate the highest standards of security, accountability, and transparency.

Note that this report refers to the 2023 incident and the above only bullet point 6. refers to the most recent incident from 2024 where Microsoft had to admit that other threat actors have had access to their systems and that Microsoft is unable to prevent further accesses to their system by these actors. Or with the words of Adam Meyers, a senior vice president at the cybersecurity firm Crowdstrike:

the hackers are deep inside Microsoft, and Microsoft hasn't been able to get them out in two months

We will maybe get a further report from the Cyber Safety Review Board on this new incident.

This new incident means that these actors have access to the source code of all Microsoft products, allowing them to identify zero-day exploits, i.e. vulnerabilities that are yet unknown to Microsoft, while attackers can exploit them any time and Microsoft will not have a fix for this available in time.

Note that Microsoft owns GitHub where a huge majority of open-source software is hosted that drives today's Internet and computer systems, thus making software supply chain attacks by these actors more likely by giving them the tools to compromise the software supply chains via GitHub itself.

Compare the Microsoft attitude to blanket their security mistakes with Google creating a documentary on their security incidents (HACKING GOOGLE) and using this rather as opportunity for advertisement. (Talking about advertisement: it is a completely new experience to watch that documentary on YouTube: no ads -- well just the whole documentary is the ad.)