JPMorgan Chase & Co. has confirmed that it recently suffered a cyber-attack that compromised its systems, although it's not sharing many details about the incident.

"We uncovered an attack by an outside adversary recently where the firm's technology environment was compromised," Kristin Lemkau, a JPMorgan Chase spokesperson, told the New York Times. "We are confident we have closed any known access points and prevented any future access in the same way."

Lemkau also stated that JPMorgan Chase had "not seen any unusual fraud activity" since the break-in was discovered. Additionally, there is "no evidence that they have taken any proprietary software," she says.

The cyber-attack is acknowledged in a brief statement on JPMorgan Chase's website. The bank declined to offer further comment to Information Security Media Group.

The Times reports that sources close to the investigation confirmed that hackers had access to dozens of JPMorgan's servers over a period of two months, and that they were able to review information about 1 million customer accounts and gain access to a list of the software applications installed on the bank's computers.

Another individual familiar with the investigation said hackers had not gained access to accountholders' financial information or Social Security numbers, and may have only viewed names, addresses and phone numbers, the report says.

The breach allegedly began in June and was not detected until late July, according to the report.

News of the breach first came to light on Aug. 27, when Bloomberg reported that Russian hackers had attacked Chase and at least one other U.S. banking institution (see: Chase Breach Investigation: Any Answers?).