The parent company of discount retail website Geeks.com has notified affected customers that a hacker may have accessed their credit card numbers and other personal information in a December incident. The website features the “hacker safe” notification from McAfee ScanAlert.

Genica Corp. discovered on Dec. 5 that a hacker may have accessed customers’ names, addresses, telephone numbers, email addresses and credit card information when he or she accessed its eCommerce website, Jerry Harken, chief of security, told customers in a letter sent Friday.

The letter was posted Monday to the Consumerist blog.

Harken told customers that Genica has reported the incident to local law enforcement, the U.S. Secret Service and Visa, and has hired an outside security firm to investigate.

The 30-day period from the time Genica discovered the hack to when the company notified affected customers falls within the vague timeframe allowed by California state law, according to Avivah Litan, Gartner vice president and research director.

A Genica representative could not be immediately reached for comment.

Websites displaying a “hacker safe” tag from ScanAlert, acquired by McAfee last October in a deal worth as much as $75 million, “can prevent 99 percent of hacker crime,” according to an site-specific information page.

A McAfee representative could not be immediately reached for comment.

Genica today activated a toll-free number to assist affected customers, who can have a fraud alert placed on their accounts at no charge.

Affected customers can call 1-888-529-6261 or 1-212-560-5108 for help.