The company was unable to detect agents of foreign intelligence services who had penetrated it because of its lack of internal security controls.
In testimony to the Senate Judiciary Committee on Tuesday, Zatko claimed that he was the victim of a data security attack.
According to the opening questions from the senators, there were many threats from employees of the indian government. The Indian government was not the only one that embedded agents in the company. Zatko said that at least one Chinese spy was employed by the company.
He said that they didn't have the ability to expel foreign intelligence agents on their own.
According to Zatko, a lack of access logging in the company's internal systems meant it was impossible to see what data had been viewed by specific employees. Zatko told the hearing that there were a lot of unauthorized data access attempts within the company.
We weren't able to expel foreign intelligence agents on our own.
Zatko made his first public appearance since his disclosure was reported by CNN and The Washington Post in August, when he appeared before the Judiciary Committee.
Zatko claimed that representatives of foreign intelligence services were able to get into the company, as well as a number of security gaps, including the fact that half of the company's 10,000 employees were able to see potentially sensitive user data.
New details given to the hearing will put Zatko back in the spotlight. In the time since the disclosures were made, lawyers for Musk sought to subpoena Zatko to present evidence in the lawsuit over whether Musk will be forced to buy or back out of the deal.
Many of Zatko's friends and former colleagues have said that they have been offered large sums of money to do interviews about Zatko's personality, work, according to new reporting from The New Yorker.
Zatko told the Judiciary Committee that he was willing to put it all on the line to improve security at the micro-blogging site.
By the time of publication, there had been no response to the request for comment.