The attack occurred in November, but wasn't discovered until Dec. 7, John Colbert, chief executive officer of Guidance, said in an interview Monday. The attack exposed data on thousands of the company's customers, including 3,800 whose names, addresses and credit card details were exposed, he said.
"A person compromised one of our servers," Colbert said. "This incident...highlights that intrusions can happen to anybody and nobody should be complacent about their security."
Guidance, one of the leading sellers of software used to investigate computer crimes, sent out letters last week to inform its customers about the breach. Some customers have already reported. "There have been a handful of cases, but we're only two weeks into this, so I don't know the total size," Colbert said.
New York City-based Kessler International received notice from Guidance on Monday, three days after it got an American Express bill for about $20,000, mostly in unauthorized charges for advertising at Google, said Michael Kessler, president of the computer-forensics investigative firm.
"We got hit pretty badly," Kessler said. "Our credit card fraud goes back to Nov. 25. If Guidance knew about it on Dec. 7, they should have immediately sent out e-mails. Why send out letters through U.S. mail while we could have blocked our credit cards?"
Regular mail was the quickest way to contact customers, according to Colbert. "We don't have e-mail addresses for everybody, and we found that their physical addresses are more permanent than their e-mail addresses," he said.
Guidance stored customer names and addresses and retained "card value verification," or CVV, numbers, Colbert said. The CVV number is a three-digit code found on the back of most credit cards that is used to prevent fraud in online and telephone sales. Visa and MasterCard prohibit sellers from retaining CVV once a transaction has been completed.
"We found that our systems were storing these numbers that were supposed to be deleted after their use," Colbert said. The company no longer stores CVV numbers, he said.
Guidance's EnCase software is used by security researchers and law enforcement agencies worldwide. The Pasadena, Calif.-based company notified all its approximately 9,500 customers about the attack and has called in the U.S. Secret Service, which has started an investigation, Colbert said.
While Kessler isn't happy, data breaches are part of business, he said. "Obviously Guidance has to do a lot of soul searching to see if they were maintaining their data as required," he said.
The intrusion at Guidance is the latest in a string of reported data security breaches this year. Since February, more than 53 million personal records have been Privacy Rights Clearinghouse., according to information compiled by the