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Microsoft Outlook Add-in Stolen 4,000 Microsoft account Credentials and Credit Card Numbers

Cybersecuritynews •Abinaya • February 12, 2026

Security researchers have identified the first documented instance of a malicious Microsoft Outlook add-in being used against users in real-world scenarios. A compromised meeting scheduler named AgreeTo was used to steal over 4,000 Microsoft account credentials, credit card numbers, and answers to banking security questions. AgreeTo began as a legitimate open-source project published to the Microsoft Office […]

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This article is one source in a clustered incident — the cluster page carries the summary, timeline and every other outlet covering it.

Weaponized Microsoft Outlook Add-ins Exploit User Credentials A dormant Microsoft Outlook add-in has been weaponized, leading to the theft of thousands of login credentials and credit card numbers. This incident marks the first known malicious Office add-in discovered in the wild, revealing a critical flaw in Microsoft's distribution of third-party tools. Additionally, a new attack technique called 'Exfil Out&Look' has been identified, allowing threat actors to exfiltrate sensitive email data without leaving forensic traces. 9 sources 40

Extracted Entities

Microsoft Outlook Add-in Stolen 4,000 Microsoft account Credentials and Credit Card Numbers

The full story

Extracted Entities

Attack Types (2)

Malware (1)

MITRE ATT&CK (1)

Platforms (2)