IDG News Service (New York Bureau) —

"The Federal Reserve System is aware that information was obtained by exploiting a temporary vulnerability in a website vendor product. The vulnerability was fixed shortly after discovery and is no longer an issue," a Federal Reserve spokesman wrote in an email. "This incident did not affect critical operations of the Federal Reserve System."

Slideshow: Anonymous, LulzSec, AntiSec, Etc.: A Brief History of Hacktivism

Slideshow: The Anonymous Hit List

The Federal Reserve did not identify the attackers, however, on Sunday, a group claiming to be affiliated with Anonymous, the loose collective of malicious hackers, posted the personal information of more than 4,000 bank executives, stating the information came from the Federal Reserve.

The Emergency Communications System (ECS), run by the Federal Reserve Bank of St. Louis, was the system attacked, according to a memo that the banking system sent out to the system's users. ECS provides financial institutions with status updates of the Federal Reserve during times of natural disaster. Attackers gained access to a database with bank executive contact information, including mailing addresses, business and phone numbers, email and fax numbers.

The Federal Reserve stated that no passwords were compromised, despite press reports to the contrary. The organization reset the contact's passwords to the system anyway as a precaution.

The group, Operation Last Resort, posted the contact information it had on the website for the Alabama Criminal Justice Information Center, after breaking into that site. Operation Last Resort is protesting what it considers to be overly severe U.S. Department of Justice prosecution of Internet activist and innovator Aaron Swartz, who recently committed suicide. Swartz faced a 35-year jail sentence and a US$1 million fine for allegedly illegally downloading millions of scholarly articles from a Massachusetts Institute of Technology network.