The U.S. Federal Reserve, the nation's central bank, detected more than 50 cybersecurity breaches between 2011 and 2015, including a handful attributed to espionage.
The Fed's Washington-based Board of Governors identified 51 information disclosures during the five-year period, according to information obtained through a Freedom of Information Act request by Reuters.
The breaches reported include only those at the Fed's Washington location and don't include any at its 12 privately owned regional branches.
The Fed classified four hacking incidents in 2012 as espionage, and there were information disclosures in two of those cases, according to the records released to Reuters. It was unclear whether information was disclosed in the other two cases, Reuters said.
Between 2012 and this year, the Fed's Washington reported 81 malicious code incidents, 54 cases of unauthorized access, and 12 cases of inappropriate use of networks or computers, Reuters reported.
The Fed didn't immediately respond to a request for comments on the Reuters report.
Earlier this year, cybercriminals made off with US$81 million in a cyberattack on the central bank of Bangladesh. The attacks on the Fed illustrate a growing trend of cyberattacks on banking institutions, some cybersecurity experts said.
It's no surprise that there were dozens of breaches at the Fed during that time period and that international cyberespionage may have been involved, said Eric O'Neil, national security strategist for security vendor CarbonBlack.
The Fed holds information about U.S. government monetary and economic policy, including upcoming decision, noted O'Neil, a former cybersecurity and counterintelligence expert at the FBI. Other nations could be targeting the Fed to get a jump on future U.S. policy shifts, he said.
"The Federal Reserve is really a gold mine for economic espionage," O'Neil added.
Attacking the Fed doesn't "sound as sexy as stealing defense secrets or military intelligence secrets, but it can be more damaging," he said. "It is a way to improve an economy at the expense of another, and unfortunately, that would be us."
The Fed is a "prominent target," added Toni Gidwani, director of research operations at security vendor ThreatConnect. Attacks on the banking system are "aimed at the heart of how money flows across the globe," she added by email.
Espionage attempts at the Fed would not be surprising, she added. "Gaining access to the Fed's data and its strategies for ensuring the health of the U.S. dollar and the broader economy would be very valuable for a number of actors -- whether it's nation states seeking to understand their exposure to swings in interest rates or individuals looking to profit by advanced knowledge of the Fed's next moves," Gidwani said.
The banking system is often a "hard target," but the potential rewards are high for attackers who have a sophisticated skill set, added Richard Ford, chief scientist at security vendor Forcepoint. "There's a certain brand of attacker who loves going after banks," he said. "That's really where the money is."
In the case of attacks on the Fed, attackers are probably looking for information, Ford said. "Information is money," he said. "There are certain pieces of information that people are looking for that can be monetized in other ways than ... moving money out."