CSRB Review Summer 2023 MEO Intrusion

www.cisa.gov • September 11, 2026

Official websites use .gov A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS A lock ( ) or https:// means you’ve safely connected to the .gov website. sensitive information only on official, secure websites.

The U.S. Department of Homeland Security released the Cyber Safety Review Board’s (CSRB) findings and recommendations following its independent review of the Summer 2023 Microsoft Exchange Online intrusion. The review detailed operational and strategic decisions that led to the intrusion and recommended specific practices for industry and government to implement to ensure an intrusion of this magnitude does not happen again. This is the third review completed by the CSRB since the Board was established in September 2021.

The full story

This article is one source in a clustered incident — the cluster page carries the summary, timeline and every other outlet covering it.

Microsoft Faces Scrutiny After Series of Cyber Breaches Microsoft has experienced multiple high-profile cyberattacks, including breaches by Russian and Chinese hackers in 2023, which compromised sensitive information from U.S. government agencies. Despite these incidents, the U.S. government continues to rely heavily on Microsoft products, raising concerns about accountability and security culture within the company. In response to criticism, Microsoft launched the Secure Future Initiative in November 2023 to overhaul its cybersecurity practices and improve its security culture. The Cyber Safety Review Board has criticized Microsoft for its inadequate security measures, emphasizing the need for significant changes. The ongoing relationship between the U.S. government and Microsoft complicates the landscape of cybersecurity accountability. As Microsoft implements its new security measures, it claims to be seeing positive results, but skepticism remains among cybersecurity experts and lawmakers. 1 sources 58

CSRB Review Summer 2023 MEO Intrusion

The full story

Extracted Entities

Countries (1)

Platforms (1)