(AP)—Experts say that the hacking of 3.6 million South Carolina tax returns is the largest cyber-attack against a state tax agency in the nation.
Paul Stephens of the Privacy Rights Clearinghouse in California says there have been larger attacks against both private companies and the federal government that revealed information that could lead to identity fraud.
State officials say the attack was mounted from a computer with an international IP address. They say the attack was found earlier this month but they have not given many details because of the ongoing investigation.
The Revenue Department says Social Security numbers, credit card information and information from businesses may have been compromised in the attack.
Tax returns as far back as 1998 were in the hacked files.
Explore further: 46,000 Twitter accounts linked to Islamic State: study