The BBB system, which has 129 branches, said a company from Kennesaw, Ga., had its computer system hacked Monday night and that the company's computers were generating thousands of counterfeit messages to businesses and consumers, purporting to be a complaint filed with the BBB against the recipient.

The incident was first reported to the BBB branch that serves the Columbus, Ga., area by one of its members, according to the alert. The spoofed e-mails were sent to thousands of businesses in the U.S. and Canada.

According to the BBB, the e-mail has a false return address of operations@bbb.org and a phishing hyperlink citing a BBB complaint case number, such as "DOCUMENTS FOR CASE #263621205." But the links direct users to a fake Web site that asks users to download documents related to the complaint. The BBB said the download is an executable file that could be a computer virus. The phishing e-mail return address of operations@bbb.org does not exist, the BBB said in the alert.

An example of the false e-mail message is also provided on the BBB Web site.