A data breach at a mortgage software firm has left some of Wall Street’s biggest banks scrambling to secure customer data.

SitusAMC, a platform used by hundreds of banks to originate and service real estate loans and mortgages, disclosed Saturday that the hack allowed cyberattackers to gain access to data on residential mortgages and potentially more sensitive information.

Some of America’s biggest financial institutions have been affected, including JPMorgan Chase, CitiGroup and Morgan Stanley, according to The New York Times, which first reported the data breach.

SitusAMC said its team became aware of the intrusion following an incident on Nov. 12. It confirmed that it had been hacked on Nov. 15, and it notified all of its residential mortgage customers last week that they may have been impacted, Bloomberg reported.

The New York-based software firm publicly disclosed the attack the same day as the Times report.

"We are in direct contact with our clients about this matter. We remain focused on analyzing any potentially affected data and will provide updates directly to our clients as our investigation progresses, SitusAMC CEO Michael Franco said in a statement shared with Bisnow on Monday.

The hackers didn’t deploy the type of encryption malware commonly used to extort companies and individuals for cash in exchange for codes that restore their data.

SitusAMC said it has successfully stopped the hackers from extending their reach into its systems, but it is still working to determine exactly what and how much data has been compromised.

“Corporate data associated with some of our clients’ relationship with SitusAMC such as accounting records and legal agreements has been impacted. The scope, nature and extent of such impact remains under investigation,” the company said in a statement.

SitusAMC is working with the FBI and has also brought in third-party advisers to address the breach.

FBI Director Kash Patel indicated in a statement that the agency was working to determine who was behind the attack.

“We remain committed to identifying those responsible and safeguarding the security of our critical infrastructure,” he said.

SitusAMC has a software platform that supports both residential and commercial loans throughout their lifecycle. It helps its customers evaluate more than $2T in commercial real estate debt each quarter and $7T in monthly residential loan valuations, according to the firm.

Alternative asset manager Stone Point Capital is the largest investor in SitusAMC, and the Public Sector Pension Investment Board, Canada’s largest public pension investment manager that’s better known as PSP Investments, purchased a minority stake in 2020, according to a press release at the time. The remaining shares are held by company executives.