Microsoft security incident history
Hacking, data breaches and other security incidents involving Microsoft, with related coverage.
Microsoft X account hacked and used in crypto price manipulation
Microsoft's X account was hacked and used in a market manipulation scheme in which a cryptocurrency price was pumped and then sold off. The specific scale of the damage and the response have not been confirmed.
Read on BleepingComputer ↗ExfilSquad claims Microsoft data breach
ExfilSquad claimed a data breach at Microsoft. Whether the breach actually occurred, its extent and the response have not been confirmed.
Read on cyfirma ↗Hacked Microsoft open-source tool used to spread malware
Impact: Theft of AI developers' passwords and distribution of malware to Claude and Gemini users
A Microsoft open-source tool was hacked and abused to steal AI developers' passwords. Malware was delivered to Claude and Gemini users, and Microsoft's open-source projects suffered a string of hacks. The specific scale of the damage and response measures have not been confirmed.
Related reports: 4 · last report →Microsoft bug exposes confidential emails to Copilot
Impact: Customers' confidential emails
A bug in Microsoft Office exposed customers' confidential emails to the Copilot AI. Microsoft disclosed the exposure caused by the bug.
Related reports: 2 · last report →Microsoft engineer salary data leaked
Impact: Engineer salary data
Salary data of Microsoft engineers was leaked. The scale and circumstances of the leak and the company's response have not been confirmed.
Read on Futurism ↗Microsoft product hacked by China, China-based support staff used
A Microsoft product was recently hacked by China. Microsoft had used China-based engineers to support the product, but no causal link between the use of these staff and the hack has been confirmed.
Read on ProPublica ↗Official Xbox social media account hacked to post crypto scam
An official Xbox social media account was hacked and used to post a cryptocurrency scam. The timing of the account compromise, the specific extent of the damage and the response have not been confirmed.
Read on TweakTown ↗DDoS attack disrupts major Microsoft services for about 9 hours
Impact: About nine hours of outages and instability in Azure, Microsoft 365 and other services
On July 30, a DDoS attack caused multiple Microsoft services, including Azure and Microsoft 365, to go down or become unstable for about nine hours. Outlook and the Starbucks app, among others, were also affected. Microsoft explained that an error in the implementation of its defenses amplified the impact of the attack.
Related reports: 4 · last report →Microsoft tightens security after China-linked hack
Microsoft was hit by a China-linked hack, after which a US federal report criticized the company's security and incident response. The company tied executive pay to tackling cyber threats. In April 2025, it cleaned up dormant Azure tenants and rotated keys to prevent a repeat of state-backed hacking.
Related reports: 3 · last report →Microsoft executive emails and source code stolen
Impact: Theft of senior executives' emails, source code and some customer secrets
Microsoft had senior executives' email compromised in an attack by a hacker group linked to Russian intelligence. The group was identified as Midnight Blizzard. Microsoft later confirmed that source code and some customer secrets had also been stolen.
Related reports: 12 · last report →Cyberattack causes Microsoft Azure service outage
Impact: Azure service outage
An outage occurred in Microsoft's Azure services. Microsoft identified a cyberattack as the cause of the outage.
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