The Securities and Exchange Commission has provided more details about how its official X account was compromised earlier this month. In a statement, the regulator confirmed that it had been the victim of a SIM swapping attack and that its X account was not secured with multi-factor authentication (MFA) at the time it was accessed.

“The SEC determined that the unauthorized party obtained control of the SEC cell phone number associated with the account in an apparent ‘SIM swap’ attack,” it said, referring to a common scam in which attackers persuade customer service representatives to transfer phone numbers to new devices. “Once in control of the phone number, the unauthorized party reset the password for the @SECGov account.”

The hack of its X account, which was taken over in order to falsely claim that bitcoin ETFs had been approved, has raised questions about SEC’s security practices. Government-run social media accounts are typically required to have MFA enabled. The fact that one as high-profile and with potentially market-moving abilities like @SECGiv would not be using the extra layer of security has already prompted questions from Congress.

In its statement, the SEC said that it asked X’s support staff to disable MFA last July following “issues” with its account access. “Once access was reestablished, MFA remained disabled until staff reenabled it after the account was compromised on January 9,” it said. “MFA currently is enabled for all SEC social media accounts that offer it.”

While the lack of MFA likely made it much easier to take over the SEC’s account, there are still numerous questions about the exploit, including how those responsible knew which phone was associated with the X account, how the unnamed telecom carrier fell for the scam and, of course, who was behind it. The regulator said it’s investigating these questions, along with the Department of Justice, FBI, Homeland Security and its own Inspector General.