Wiz Reports: Microsoft Attack Using Azure AD Token Forging Technique Has Wider Implications Beyond Outlook
On July 21, 2023, it was revealed that the recent breach of Microsoft’s email services by the Chinese state-sponsored group Storm-0558 is more extensive than initially suspected. According to cloud security firm Wiz, the attack exploited an inactive consumer signing key from Microsoft accounts (MSA) to forge Azure Active Directory (Azure AD) tokens, allowing unauthorized access not just to Outlook Web Access (OWA) and Outlook.com, but potentially to a wide range of Azure AD applications. This includes major platforms like OneDrive, SharePoint, and Teams, as well as customer applications utilizing "Login with Microsoft" features, and certain multi-tenant applications under specific conditions. Wiz’s CTO, Ami Luttwak, emphasized, "Everything in the world of Microsoft leverages Azure Active Directory auth tokens for access," highlighting the far-reaching implications of this vulnerability.