After a security enthusiast discovered a loophole that allowed him to register a valid SSL certificate for Microsoft's live.fi domain, he tried to responsibly disclose the issue. But instead of thanks he got locked out of his email, phone, Xbox and online storage accounts.
The issue was discovered by a Finnish man who works as an IT manager for a company in the industrial sector. He talked to the IDG News Service, but requested anonymity.
Microsoft's Outlook.com email service allows users to have multiple email addresses called aliases under a single account. At the moment, the service only allows aliases to be created on the @outlook.com domain, but several months ago more domains were available.
Around six months ago the Finnish IT manager, who already had a @live.fi and @live.com address, got the idea to check if he could register any privileged usernames as his additional aliases.
Privileged usernames like admin@, administrator@, postmaster@, hostmaster@ and webmaster@ are typically reserved for use by domain name owners for administrative purposes, but the IT manager managed to register email@example.com, firstname.lastname@example.org and email@example.com as his aliases because Microsoft did not block them.
Initially he thought that he might receive potentially sensitive email messages intended for the domain owner and that he would then report the issue, but as time passed, no email came for those addresses. Then, in January he got the idea to try to obtain an SSL certificate using one of the addresses.
He chose a certificate authority called Comodo because the company offers certificates for free that are valid for 90 days and because it accepts domain ownership verification through admin-type email addresses.
According to the IT manager, he obtained the certificate late on January 26 and the whole process took around 10 minutes which made him believe that it was fully automated. The following day he reported the issue to CERT-FI, which is part of the National Cyber Security Centre Finland.
He also claims that he reported the issue to an email address listed as contact for the live.fi domain on Jan. 31 and to firstname.lastname@example.org on Feb. 24, but he received no response from either address. It's worth noting that the proper contact email at Microsoft for reporting vulnerabilities is email@example.com, not firstname.lastname@example.org. However, according to a Microsoft blog post from 2006, there should be an automatic response from email@example.com with information about the proper contact.
Microsoft issued an update Monday to blacklist the improperly issued certificate, but not before suspending the IT manager's account on March 12. This locked him out not only from his email, but also OneDrive, Xbox Live, Lumia phone and other Microsoft services. Microsoft finally unlocked his account today.
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