"The security of Xbox Live members is of the utmost importance, which is why we consistently take measures to protect Xbox Live against ever-changing threats," a Microsoft spokesperson stated, "Xbox Live has not been hacked. Microsoft can confirm that there has been no breach to the security of our Xbox Live service."
The spokesperson then reassured that Microsoft was actively working on phish prevention. According to the statement, the company is currently "working closely with affected members who have been in touch with us to investigate and/or resolve any unauthorized changes to their accounts resulting from phishing scams, warning people against opening unsolicited e-mails which may contain spyware and other malware that can access personal information contained on their computer without their knowledge or permission," and "reminding all customers that they should be very careful to keep all personal information secure whenever online and never supply e-mail addresses, passwords or credit card information to strangers."
The spokesperson concluded, "Microsoft remains vigilant at all times regarding the security of Xbox Live customers" and advised affected customers to call Xbox Live Customer Service or visit the official site here.