SecurID is used for two-factor authentication purposes. The technology is available from RSA in the form of hardware and software tokens that are capable of generating random one-time passwords every 60 seconds.

The technology is designed to be used in conjunction with passwords to deliver a second layer of authentication for accessing systems and networks. Over 25,000 enterprises, many of them in the financial sector and government, currently use SecurID tokens to protect access to high-value applications and data.

Though RSA has not disclosed which or how much SecurID information was stolen, the mere fact that the company is warning of reduced effectiveness is troubling, said John Pescatore, an analyst with Gartner.

That statement guarantees that the breach is a "big deal for SecurID users," Pescatore said.

"SecurID tokens are very expensive and users dislike them, but they have always been a strong replacement for reusable passwords," he said. "[But] if the security provided is at risk, the pain may be more than the gain."