Office 365 is Microsoft's cloud productivity suite, whose identity, email, and data controls make its vulnerabilities and security advisories consequential.
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Office 365 is Microsoft’s cloud-hosted productivity and collaboration service, encompassing Exchange Online email, SharePoint, OneDrive, Teams, and web and desktop Office applications. Because these services store communications and business documents in a shared cloud environment, the tag includes both attacks against the platform and security issues arising from tenant configuration, identity, and connected applications.
Material risks include phishing or stolen credentials leading to account takeover, malicious OAuth applications gaining delegated access, mailbox forwarding rules, and excessive external sharing of files. Effective defenses include phishing-resistant multifactor authentication, conditional-access policies, least-privilege administration, controlled app consent, data-loss prevention, and review of audit and sign-in logs. Security teams must also track Microsoft advisories and client vulnerabilities, preserve cloud evidence for investigations, and apply retention, privacy, and compliance controls appropriate to the data stored in the tenant.
The U.S. Department of Homeland Security's Cyber Safety Review Board (CSRB) has released a scathing report on how Microsoft handled its 2023 Exchange Online attack, warning that the company needs to do better at securing data and be more truthful about how threat actors stole an Azure signing key. [...]
CISA calls for 'fundamental, security-focused reforms' to happen ASAP, delaying work on other software A review of the June 2023 attack on Microsoft's Exchange Online hosted email service – which saw accounts used by senior US officials compromised by a China-linked group called "Storm-0558" – has found that the incident would have been preventable save for Microsoft's lax infosec culture and sub-par cloud security precautions.…
CISA calls for 'fundamental, security-focused reforms' to happen ASAP, delaying work on other software A review of the June 2023 attack on Microsoft's Exchange Online hosted email service – which saw accounts used by senior US officials compromised by a China-linked group called "Storm-0558" – has found that the incident would have been preventable save for Microsoft's lax infosec culture and sub-par cloud security precautions.…