A security breach last year on a server in Montana's health department may have compromised confidential information about more than one million people, state officials announced Tuesday, adding that the identities of the intruders and the extent of damage from the hack are still unclear.

The state government said that it would send notifications to 1.3 million people, including residents, former residents and families of dead residents, whose personal information may have been accessed by hackers during the attack that occurred last July, but went undiscovered until May 22 when a malware was detected on the health agency's server, Associated Press, or AP, reported.

“There is no information, no indication, that the hackers really accessed any of this information or used it inappropriately,” Richard Opper, director of the state's Department of Public Health and Human Services, told AP. “We are erring on the side of displaying an overabundance of caution.”

The information on the affected server included names, addresses, birth dates, Social Security numbers and medical records related to health assessments, diagnoses, treatment, prescriptions and insurance, AP reported, adding that while state officials have not found evidence of any information having been stolen, they have offered a free credit-monitoring service and identity-fraud insurance for a year to all the potential victims.

In addition to the 1.3 million people, nearly 3,100 department employees and contractors have also been notified of the breach because the compromised server contained information about their bank accounts, according to officials, who also stated that security upgrades have been implemented since the hacking was discovered.

Montana, which has a population of nearly 1 million, experiences an average of 17,000 hacking attempts on the state's computer system every hour, or nearly six billion attempts a year, according to Opper, who also said that the latest breach was the first incident when hackers broke into a state agency’s system on such a large scale, Reuters reported.

“This type of unauthorized access is not unique to Montana," Ron Baldwin, Montana’s chief information officer, told AP. "This is sort of the nature of the world we live in today.”