**FOR IMMEDIATE RELEASE**
**WASHINGTON, D.C. –** The Federal Bureau of Investigation (FBI) has issued a formal cybersecurity alert concerning a critical vulnerability affecting Microsoft Outlook and OneDrive applications.
**WHO:** The Federal Bureau of Investigation (FBI), in coordination with the Cybersecurity and Infrastructure Security Agency (CISA).
**WHAT:** A coordinated law enforcement and intelligence community warning regarding an active exploitation campaign. The alert targets a previously undisclosed security flaw that permits remote code execution and unauthorized data exfiltration through the integration of Microsoft Outlook and OneDrive.
**WHEN:** The official notice was disseminated to private sector partners and federal agencies at 0900 hours Eastern Standard Time today. Intelligence suggests the exploitation campaign has been active for approximately seventy-two hours prior to the public disclosure.
**WHERE:** The vulnerability affects enterprise and consumer environments globally. The FBI has confirmed indicators of compromise across multiple critical infrastructure sectors within the United States, as well as allied nations. The attack vector appears to originate from a known advanced persistent threat (APT) group based in Eastern Europe.
**WHY:** The exploitation leverages a chain of legitimate synchronisation protocols between Outlook and OneDrive. This allows malicious actors to bypass standard security filters, deploy backdoor access, and harvest confidential communications and stored files without triggering conventional detection systems. The FBI assesses the objective as long-term espionage and data theft.
**HOW:** The attack is initiated via a targeted phishing email containing an attachment that appears to be a legitimate OneDrive file invitation. Upon opening the attachment, a malicious script executes within the user's Outlook client, granting the threat actor persistent access to the user's mailbox and cloud storage. The FBI advises all users to immediately disable automatic link previews, verify all file-sharing requests via out-of-band communication, and apply the latest patch released by Microsoft Corporation at 1100 hours today.
**Update:** The FBI urges any organization or individual detecting suspicious activity to report the incident to the Internet Crime Complaint Center (IC