Storm-0558: Understanding How Microsoft Failed to Protect Itself

You’re undoubtedly familiar with the so-called Storm-0558 attacks from July 2023. If not a quick recap: these attacks (widely attributed as the work of the Chinese government) compromised a number of high-value Exchange Online mailboxes, including the US Secretary of Read More …

Analysis of Storm-0558 techniques for unauthorized email access

As described in more detail in our July 11 blogs, Storm-0558 is a China-based threat actor with espionage objectives. Beginning May 15, 2023, Storm-0558 used forged authentication tokens to access user email from approximately 25 organizations, including government agencies and Read More …