Less sensitive personal data such as names, birth dates and addresses of another 500,000 people may have also been compromised in the breach, state officials said today.
Today's marks the second time in three days that Utah state officials have upped their estimates of a March 30 intrusion into a server containing Medicaid claims data on Utah residents.
According to the Utah Department of Technology Services (DTS) and the Utah Department of Health (UDOH), the breach stemmed from a configuration error at the user authentication layer. The error allowed attackers, believed to be operating out of Eastern Europe, to bypass the network, perimeter and application level security controls that were in place to protect the server.
Initially, state officials said the intrusion had . Each record could include Social Security Numbers, names, birth dates, addresses, tax identification numbers and treatment codes.
On Friday, the two organizations released saying forensics investigations showed the breach to be larger than initially thought. In addition to Medicaid data, the breached information included data about recipients of the state's Children's Health Insurance Plans (CHIP). And rather than 24,000 claims, the hackers had actually accessed 24,000 files, each one of which potentially contained personal data on hundreds of individuals.
Early on Monday, Utah state officials changed their numbers again. In a statement, DTS and UDOH officials said ongoing investigations showed that the compromised data included Social Security Numbers belonging to about 255,000 people whose providers had contacted the UDOH to verify their Medicaid eligibility.
"The victims are likely to be people who have visited a health care provider in the past four months," the statement said. "Some may be Medicaid or CHIP recipients; others are individuals whose health care providers were unsure as to their status as Medicaid recipients."
The state has begun notifying affected individuals about the compromise. Those who had their SSNs stolen will receive one year's worth of free credit monitoring services.
Attacks that take advantage of weak authentication mechanisms continue to be a major problem for enterprises. Though the issue is well understood, many companies with otherwise sound defenses continue to get breached because of their reliance on default or easy-to-guess passwords and knowledge-based authentication (KBA) mechanisms for controlling access to critical network assets and systems.
A recent breach at that exposed debit and credit card data belonging to about 1.5 million people is thought to have resulted from an authentication vulnerability.
Jaikumar Vijayan covers data security and privacy issues, financial services security and e-voting for Computerworld. Follow Jaikumar on Twitter at or subscribe to . His e-mail address is .
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