The Week at a Glance

  • 🔴 ACR Stealer credential campaign is actively hitting enterprises - attackers are stealing browser credentials and authentication tokens right now; your accounts and data are at direct risk until defensive action is taken.
  • 🔴 Exchange Server 2016/2019 security support ends in October 2026, with no extensions - organizations still running on-premises Exchange have roughly 90 days to migrate or face permanently unpatched vulnerabilities.
  • 🟡 Passkeys are now the default sign-in method in Microsoft Entra ID - this is a significant change to how your workforce authenticates; employee communication and help desk preparation are needed within 30 days.
  • 🟡 AI agent governance and data-in-motion protection have reached general availability - organizations deploying Copilot or other AI tools now have production-ready controls available; planning is needed to activate them before exposure grows.

Sources: Microsoft Security Blog - ACR Stealer · Exchange Team Blog - ESU End Date · Microsoft Security Blog - Passkeys Default

Why This Week Matters

Three separate threat vectors are converging at once: active credential theft targeting enterprise browsers, a closing window on legacy email server support, and AI tools that employees are already using to move sensitive data outside controlled boundaries. The single thing leadership must understand is that the perimeter no longer exists in a meaningful sense; data now flows through AI prompts, unmanaged SaaS tools, and browser sessions, and the controls to govern that flow are available today but require a deliberate decision to activate them. Organizations that treat these items as an IT to-do list rather than a risk governance decision will face a measurably wider exposure by Q4.

Sources: Microsoft Security Blog - ACR Stealer · Microsoft Entra Blog - Data in Motion · Microsoft Security Blog - Secure Future Initiative

Risk & Compliance

  • 🔴 ACR Stealer credential campaign: Active attacks observed from late April through mid-June 2026 are stealing browser-stored credentials, authentication tokens, and sensitive documents from enterprise environments using convincing fake prompts; stolen tokens bypass multi-factor authentication entirely, creating direct SOC 2, HIPAA, and cyber insurance exposure - engage your security team immediately.

  • 🔴 Exchange Server 2016/2019 ESU program ends October 2026: Microsoft has confirmed no further extensions; after October, any vulnerabilities discovered in on-premises Exchange will go permanently unpatched, creating a regulatory and cyber insurance liability that grows with every passing month - migration planning must begin now to meet that deadline.

  • 🔴 July 2026 Exchange Server security updates released: Critical security patches are available right now for Exchange SE, 2019, and 2016 - organizations on the ESU program that have not yet applied the July update are running unpatched servers today; verify with your IT team that these patches have been applied.

  • 🟡 Passkeys as the default authentication method in Entra ID: Microsoft has made passkeys the default sign-in experience in Entra ID, replacing SMS and voice as primary methods; this closes a well-documented phishing vulnerability and strengthens least-privilege enforcement at the identity layer, but it will change the sign-in experience for every user - proactive communication is needed within 30 days to avoid unnecessary help desk volume.

  • 🟡 ShinyHunters OAuth abuse targeting SaaS applications: Microsoft Threat Intelligence has identified active campaigns using voice phishing, supply-chain compromise, and misconfigured guest access to hijack OAuth-connected SaaS applications; this directly threatens any business-critical SaaS tool connected to your Entra ID tenant - review guest access permissions and OAuth app authorizations with your IT security team.

  • 🟡 AI agent identity governance now generally available: AI agents operating in enterprise environments have historically used shared credentials with no access boundaries, creating an ungoverned privilege gap; production controls to assign and govern agent identities are now available, relevant to NIST CSF and SOC 2 reviews - schedule deployment planning within 30 days for organizations actively using Copilot agents or Power Platform automation.

  • 🟡 Data loss prevention for sensitive data in motion across SaaS and AI apps: Employees are actively pasting sensitive information into AI prompts and uploading work files to personal cloud storage; Microsoft Purview combined with Entra Internet Access now provides network-level controls to govern that behavior, relevant to HIPAA, GDPR, and state privacy laws - organizations without these controls active are accepting data-exfiltration risk that is difficult to detect after the fact.

  • 🟡 MCP security risks in production AI agent deployments: The Model Context Protocol, now widely used to connect AI agents to enterprise tools and data, introduces trust boundaries that most organizations have not yet formally assessed; any AI agent that can call external tools or access internal systems should be treated as software with access rights, not a chat interface - this belongs in your next security review cycle.

  • 🟡 AsyncAPI npm supply chain compromise: Threat actors compromised widely trusted developer packages and used legitimate software delivery pipelines to distribute malware; organizations with internal software development teams should verify whether these packages are used in any production or internal tooling, relevant to CMMC and SOC 2 supply chain controls.

  • 🟡 GigaWiper destructive backdoor: This newly documented malware combines data-wiping and ransomware capabilities into a single tool, meaning an infection can destroy data rather than merely encrypt it; confirm with your security team that endpoint detection coverage is current, as this directly affects recovery time objectives and cyber insurance claims.

  • 🟢 Microsoft Purview DLP to restrict Copilot processing of external emails: A new control to prevent Copilot from processing emails from outside your organization is in preview now, with general availability targeted for January 2027; organizations with HIPAA or GDPR obligations around email data should evaluate this for inclusion in their Copilot governance policy planning.

  • 🟢 Purview Data Lifecycle Management - archive OneDrive and SharePoint files under retention: Inactive files subject to retention policies will be movable to lower-cost storage without losing discoverability or compliance standing; preview in August 2026 and general availability in September 2026 - relevant for organizations managing storage costs alongside e-discovery or regulatory retention requirements.

  • 🟢 Purview DLP enrichment of Defender alerts via Graph API: DLP event data will be directly accessible in the same API used by security tools and SIEM platforms, simplifying automated reporting and compliance workflows; relevant for organizations in active SOC 2 audits or those building integrated compliance dashboards.

Sources: Microsoft Security Blog · Exchange Team Blog · Microsoft Entra Blog

What Your Employees Will Notice

  • Sign-in experience is changing. Passkeys are now the default authentication method in Microsoft Entra ID. Employees who previously used SMS codes or phone calls to verify their identity will be guided toward passkeys - a fingerprint, face scan, or device PIN. This is more secure and faster once set up, but it is unfamiliar; expect questions and brief friction during transition.

  • Copilot is getting meaningfully smarter. OpenAI’s GPT-5.6 is now live in Microsoft 365 Copilot across Word, Excel, PowerPoint, and Chat. Employees who use Copilot regularly will notice improved reasoning on complex, multi-step tasks. No action is required; the upgrade is automatic.

  • Email recall now works across organizations. The long-standing limitation that prevented recalling a mistakenly sent email from an external recipient has been lifted. Employees can now recall messages sent to users in other organizations, a frequently requested capability that reduces the risk of accidental disclosure.

  • Remote desktop sessions will be more stable. For employees using Windows 365 Cloud PCs or Azure Virtual Desktop, a network reliability improvement called RDP Multipath with redundant TCP is now live. Sessions should drop less frequently in environments with unstable connections or VPN routing.

Sources: Microsoft Security Blog - Passkeys · Microsoft 365 Copilot Blog · Exchange Team Blog - Cross-Tenant Recall

What Your Help Desk Should Expect

  • Passkey setup questions will spike. The shift to passkeys as the default will generate a wave of “how do I set this up” and “I can’t sign in” tickets, particularly from employees on older devices or those who rely on shared workstations. Prepare step-by-step guides and consider proactive communication before the change reaches your workforce broadly.

  • SMS/voice authentication confusion. The new model for SMS and voice authentication in Entra ID changes how these fallback methods work. Employees who rely on phone-based verification as their primary method may find themselves unable to authenticate in the usual way. Help desk staff need to be briefed on the new flow before tickets arrive.

  • Cross-tenant message recall inquiries. Now that employees can recall emails sent to external recipients, expect questions about how it works, when it succeeds, and whether a recall was confirmed. This is a net-positive capability but an unfamiliar one.

  • Copilot behavior changes. Some employees will notice Copilot responding differently - better in most cases, but occasionally with different formatting or phrasing than they expected. These are not errors; they reflect the GPT-5.6 upgrade.

Sources: Microsoft Security Blog - Passkeys · Exchange Team Blog - Cross-Tenant Recall · Microsoft 365 Copilot Blog

Cost & Licensing

  • Advanced Intune Suite capabilities are now included in existing Microsoft 365 E5 licenses. As of July 1, 2026, organizations licensed for Microsoft 365 E5 gain access to advanced endpoint management capabilities - including tools for reducing standing privilege, modernizing certificate management, and improving IT response times - at no additional cost. Select capabilities are also now available in Microsoft 365 E3. If your organization is currently paying for standalone Intune Suite add-ons, review whether those are now redundant.

  • Exchange Server migration costs belong in the 2026 budget now. With the Exchange 2016/2019 support deadline confirmed as October 2026 and no extensions forthcoming, organizations that have not yet migrated to Exchange Online or Exchange Server Subscription Edition should treat migration as a current-year capital priority, not a future planning item.

  • Purview file archiving will reduce SharePoint and OneDrive storage costs starting September 2026. The upcoming ability to move inactive retention-covered files to lower-cost archive storage provides a concrete spend optimization opportunity for organizations with large SharePoint or OneDrive footprints. Finance and IT should evaluate potential savings during the preview period beginning August 2026.

Sources: Intune Blog - E3/E5 Packaging · Exchange Team Blog - ESU End Date · M365 Roadmap - Purview Archiving

Planning Horizon

Immediate - within 7 days:

  • Immediate - ACR Stealer credential campaign: Direct your security team to review Defender alerts for ClickFix-based lures and validate that endpoint detection coverage addresses browser credential theft; escalate to incident response if any affected activity is found.

  • Immediate - July 2026 Exchange Server security updates: Confirm with IT that the July 2026 security patches have been applied to all on-premises Exchange servers; unpatched servers are an active vulnerability today.

  • Immediate - ShinyHunters OAuth abuse: Request an audit of OAuth application authorizations and guest access configurations across your Entra ID tenant to identify over-permissioned connections that this threat actor exploits.

Within 30 days:

  • Within 30 days - Passkeys as the default authentication method: Plan and approve employee communication and help desk readiness before passkey prompts reach your workforce broadly, and confirm that device compatibility has been assessed for any shared or legacy workstations.

  • Within 30 days - AI agent identity governance: Schedule a planning session to assign governed identities and least-privilege access policies to any AI agents or Copilot automations currently operating in your environment.

  • Within 30 days - Data loss prevention for SaaS and AI traffic: Approve an assessment of whether network-level DLP controls via Purview and Entra Internet Access are configured to cover employee use of generative AI tools and external SaaS applications.

  • Within 30 days - MCP security review: Add AI agent tool-access boundaries to the agenda for your next security governance review, particularly if your organization is running any agents connected to internal systems or data.

  • Within 30 days - Advanced Intune Suite now in E3/E5: Direct IT to audit current Intune add-on subscriptions against newly included capabilities to identify any license redundancy and recapture spend.

Within 90 days:

  • Within 90 days - Exchange Server 2016/2019 migration: Secure executive approval and budget for migration to Exchange Online or Exchange Server SE before the October 2026 hard cutoff, after which no further security patches will be issued for any remaining on-premises instances.

  • Within 90 days - Purview DLP for external email in Copilot: Begin policy design for restricting Copilot’s processing of external emails ahead of the January 2027 general availability date, particularly if your organization handles regulated data via email.

  • Within 90 days - Purview file archiving for OneDrive and SharePoint: Evaluate retention-covered file volumes ahead of the August 2026 preview to identify storage cost savings and confirm that archiving policies align with your e-discovery and compliance obligations.

Sources: Microsoft Security Blog · Exchange Team Blog · Microsoft Entra Blog

If You Take No Action

ACR Stealer credential theft: Stolen authentication tokens allow attackers to access your Microsoft 365 environment, email, files, and financial systems without needing a password, even if multi-factor authentication is enabled. A successful breach of this type is a reportable incident under HIPAA, GDPR, and most state privacy laws, and is increasingly cited by cyber insurers as grounds for claim denial if reasonable preventive controls were not in place. The cost of a single account takeover routinely exceeds the cost of the preventive measures.

Exchange Server 2016/2019 reaching end of security support: After October 2026, every new vulnerability discovered in Exchange 2016/2019 - and researchers will continue to find them - will remain permanently unpatched. On-premises Exchange servers are consistently among the highest-value targets in enterprise ransomware and nation-state campaigns. Running unpatched Exchange is widely treated as a material control failure by cyber insurers, auditors assessing SOC 2, and regulators under HIPAA. The cost of a remediation after a breach will far exceed the cost of migration before October.

AI data-in-motion controls not activated: Without network-level data loss prevention, employees will continue to paste regulated data, customer information, and confidential business content into external AI tools and personal cloud storage with no organizational visibility or control. Regulatory bodies assessing HIPAA and GDPR compliance are increasingly treating AI prompt data as a covered data flow; the absence of controls is a documented gap your organization cannot easily explain in an audit.

Sources: Microsoft Security Blog - ACR Stealer · Exchange Team Blog - ESU End Date · Microsoft Entra Blog - Data in Motion