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Microsoft Confirms Data Breach, But Claims Numbers Are Exaggerated

Microsoft has confirmed that it inadvertently exposed information related to prospective customers, but claims that the company which reported the incident has exaggerated the numbers.

Threat intelligence firm SOCRadar revealed on Wednesday that it has identified many misconfigured cloud storage systems, including six large buckets that stored information associated with 150,000 companies across 123 countries.

These buckets, which the firm has dubbed BlueBleed, included a misconfigured Azure Blob Storage instance allegedly containing information on more than 65,000 entities in 111 countries. SOCRadar described it as “one of the most significant B2B leaks”.

SOCRadar said the exposed data belonged to Microsoft and it totaled 2.4 Tb of files collected between 2017 and August 2022. The exposed information allegedly included over 335,000 emails, 133,000 projects, and 548,000 users.

The company said the leak included proof-of-execution (PoE) and statement of work (SoW) documents, user information, product orders and offers, project details, and personal information.

Microsoft confirmed on Wednesday that a misconfigured endpoint exposed data, which the company said was related to “business transaction data corresponding to interactions between Microsoft and prospective customers”. The tech giant said it quickly addressed the issue and notified impacted customers.

“The business transaction data included names, email addresses, email content, company name, and phone numbers, and may have included attached files relating to business between a customer and Microsoft or an authorized Microsoft partner. The issue was caused by an unintentional misconfiguration on an endpoint that is not in use across the Microsoft ecosystem and was not the result of a security vulnerability,” Microsoft explained.

[ Read: Misconfigured Public Cloud Databases Attacked Within Hours of Deployment ]

The tech giant has thanked SOCRadar, but it’s not happy with the company’s blog post, claiming that it greatly exaggerates the scope of the issue and the numbers involved.

“Our in-depth investigation and analysis of the data set shows duplicate information, with multiple references to the same emails, projects, and users,” Microsoft pointed out.

SOCRadar has also made available a free tool that companies can use to find out if their data was exposed in one of the BlueBleed buckets. Microsoft is disappointed that this tool has been publicly released, saying that it’s “not in the best interest of ensuring customer privacy or security and potentially exposing them to unnecessary risk”.

The company believes such tools should include a verification system to ensure that a user can only look for data pertaining to them, and not to other users.

*description of SOCRadar tool updated

Related: Critical Vulnerabilities in Azure PostgreSQL Exposed User Databases

Related: Microsoft Confirms 'NotLegit' Azure Flaw Exposed Source Code Repositories

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Eduard Kovacs (@EduardKovacs) is a contributing editor at SecurityWeek. He worked as a high school IT teacher for two years before starting a career in journalism as Softpedia’s security news reporter. Eduard holds a bachelor’s degree in industrial informatics and a master’s degree in computer techniques applied in electrical engineering.