On the heels of a trove of 773 million emails, and tens of tens of millions of passwords, from quite a lot of domains getting leaked in January, Microsoft has confronted one other breach affecting its web-based e mail companies.

Microsoft has confirmed to TechCrunch {that a} sure “restricted” quantity of people that use net e mail companies managed by Microsoft — which cowl companies like and — had their accounts compromised.

In response to an e mail Microsoft has despatched out to affected customers (the reader who tipped us off obtained his late Friday night), malicious hackers have been doubtlessly capable of entry an affected consumer’s e-mail handle, folder names, the topic strains of e-mails, and the names of different e-mail addresses the consumer communicates with — “however not the content material of any e-mails or attachments,” nor — it appears — login credentials like passwords.

Microsoft remains to be recommending that affected customers change their passwords regardless.

The breach occurred between January 1 and March 28, Microsoft’s letter to customers stated. 

The hackers obtained into the system by compromising a buyer assist agent’s credentials, in line with the letter. As soon as recognized, these credentials have been disabled. Microsoft informed customers that it didn’t know what information was seen by the hackers or why, however cautioned that customers would possibly consequently see extra phishing or spam emails consequently. “You have to be cautious when receiving any e-mails from any deceptive area title, any e-mail that requests private data or cost, or any unsolicited request from an untrusted supply.”

We’re printing the total textual content of the e-mail beneath, however a separate e mail despatched to us, from Microsoft’s Info Safety and Governance crew, confirmed among the primary particulars, including that it has elevated detection and monitoring on these accounts affected.

Microsoft just lately turned conscious of a difficulty involving unauthorized entry to some prospects’ web-based e mail accounts by cybercriminals. We addressed this scheme by disabling the compromised credentials to the restricted set of focused accounts, whereas additionally blocking the perpetrators’ entry. A restricted variety of shopper accounts have been impacted, and we’ve got notified all impacted prospects. Out of an abundance of warning, we additionally elevated detection and monitoring to additional shield affected accounts. 

No enterprise prospects are affected, TechCrunch understands.

Proper now, a number of query marks stay. It’s unclear precisely how folks folks or accounts have been affected, nor through which territories they’re positioned — however evidently no less than some have been within the European Union, since Microsoft additionally offers data for contacting Microsoft’s information safety officer within the area.

We additionally don’t know the way the agent’s credentials have been compromised, or if the agent was a Microsoft worker, or if the individual labored for a 3rd occasion offering assist companies. And Microsoft has not defined the way it found the breach.

We have now requested Microsoft all the above and can replace this put up as we be taught extra.

On this age the place cybersecurity breaches get revealed every day, e mail is likely one of the mostly leaked items of private data. There’s even been a website created devoted to serving to folks determine if they’re amongst those that have been hacked. Have I Been Pwned, as the location known as, now has over 7.eight billion e mail addresses in its database.

We’ll replace this put up as we be taught extra. The letter from Microsoft to affected customers follows.

Expensive Buyer

Microsoft is dedicated to offering our prospects with transparency. As a part of sustaining this belief and dedication to you, we’re informing you of a current occasion that affected your Microsoft-managed e mail account.

We have now recognized {that a} Microsoft assist agent’s credentials have been compromised, enabling people exterior Microsoft to entry data inside your Microsoft e mail account. This unauthorized entry may have allowed unauthorized events to entry and/or view data associated to your e mail account (resembling your e-mail handle, folder names, the topic strains of e-mails, and the names of different e-mail addresses you talk with), however not the content material of any e-mails or attachments, between January 1st 2019 and March 28th 2019.

Upon consciousness of this concern, Microsoft instantly disabled the compromised credentials, prohibiting their use for any additional unauthorized entry. Our information signifies that account-related data (however not the content material of any e-mails) may have been seen, however Microsoft has no indication why that data was seen or the way it could have been used. In consequence, you could obtain phishing emails or different spam mails. You have to be cautious when receiving any e-mails from any deceptive area title, any e-mail that requests private data or cost, or any unsolicited request from an untrusted supply (you’ll be able to learn extra about phishing assaults at windows/safety/threat-protection/intelligence/phishing).

It is very important notice that your e mail login credentials weren’t immediately impacted by this incident. Nevertheless, out of warning, it is best to reset your password to your account.

Should you require additional help, or have any further questions or considerations, please be happy to achieve out to our Incident Response Group at If you’re a citizen of European Union, you may additionally contact Microsoft’s Knowledge Safety Officer at:

EU Knowledge Safety Officer
Microsoft Eire Operations Ltd
One Microsoft Place,
South County Enterprise Park,
Leopardstown, Dublin 18, Eire

Microsoft regrets any inconvenience attributable to this concern. Please be assured that Microsoft takes information safety very critically and has engaged its inside safety and privateness groups within the investigation and determination of the problem, in addition to further hardening of programs and processes to stop such recurrence.


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