US-CERT is warning that al-Qaida may soon attempt cyberattacks on the stock exchange and banking websites. The Department of Homeland Security told CNN there has been no corroboration of the threat, which was reportedly posted on a website and discovered Nov. 27.

According to the Associated Press report on Forbes.com, the threat alludes to attacks beginning Dec. 1, running through the "infidel New Year." It calls for all Muslims to support a cyberjihad in support of the Muslim prisoners held by U.S. soldiers at Guantanamo Bay.

US-CERT, part of DHS, sent out the alert, but it has "no information to collaborate the threat," said Joanna Gonzalez, a DHS spokeswoman. The alert was "really sent out of an abundance of caution," she added.

Such alerts are "not uncommon," Gonzalez said, although she declined to give details about how often US-CERT issues the alerts. Asked if al-Qaida has the ability to carry out such a threat, Gonzalez said she didn’t have that information.

Al-Qaida has not shown either the desire or skill to attack the United States using the Internet, so some experts are skeptical. Others believe that the call for the jihad could potentially have an effect on these systems, depending upon the skills of those involved.

On the SANS Internet Storm Center website, handler Johannes Ullrich recommends, "Make sure you follow best practices and keep your guard up. It’s probably not going to be al-Qaida, but someone will probe your defense tomorrow as they did today. And whatever helps against them will help if al-Qaida should launch a cyberattack after all."

Currently, the Financial Services Information Sharing and Analysis Center (FS/ISAC) has ranked the threat climate as "low."

-Compiled by Shawna McAlearney
(IDG News Service contributed to this report.)