Breach Notification , Healthcare , Industry Specific

Nearly 534,000 Affected in Data Theft at Managed Care Org

Wisconsin Nonprofit Says Attackers Also Tried to Encrypt Systems, But They Failed
Nearly 534,000 Affected in Data Theft at Managed Care Org
Group Health Collaborative of South Central Wisconsin is notifying nearly 534,000 individuals of a recent data theft incident. (Image: GHC-SCW)

A Wisconsin nonprofit managed care organization is notifying nearly 534,000 individuals that their protected health information was copied and stolen in a recent attack by a "foreign ransomware gang" that also attempted - but failed - to encrypt the group's IT systems.

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Group Health Cooperative of South Central Wisconsin, which provides insurance and a range of primary and specialty care services, in a report to the Maine attorney general's office said the incident discovered in January compromised information - including Social Security numbers - for 533,809 individuals, including 107 Maine residents.

The Madison, Wisconsin-based organization also on Monday reported the HIPAA breach to the U.S. Department of Health and Human Services as a hacking/IT incident involving a network server.

GHC-SCW in a breach notice said that in the early morning hours of Jan. 25 it detected unauthorized access to its network. The organization's IT team "purposefully isolated and secured our network, causing several of our systems to be temporarily unavailable."

The attacker attempted to encrypt the organization's system but was unsuccessful, GHC-SCW said.

"The fact that the ransomware was unsuccessful with encrypting the data could mean that the stored data - data at rest - was well-protected, perhaps through strong access controls, or being monitored," said Tom Walsh, president of privacy and security consultancy tw-Security. "With ransomware now being offered as a service, it could also mean that the ransomware was being used by inexperienced attackers," he said.

GHC-SCW reported the incident to the FBI, worked with the Cybersecurity and Infrastructure Security Agency and hired external cyber incident response resources to assist in the restoration of its systems and the investigation into the attack, the entity's breach notice said.

On Feb. 9, during the investigation, GHC-SCW discovered indications that the attacker had copied some of GHC-SCW's data, including patient and plan member information.

"The PHI that the attacker stole may have included member/patient name, address, telephone number, email address, date of birth and/or death, Social Security number, member number, and Medicare and/or Medicaid number," GHC-SCW said.

"Our discovery was confirmed when the attacker, a foreign ransomware gang, contacted GHC-SCW claiming responsibility for the attack and stealing our data," the organization said.

Blog site reported Wednesday that on March 9 ransomware group BlackSuit claimed responsibility for the GHC-SCW attack in a post on its dark web leak site.

HHS' Health Sector Cybersecurity Coordination Center in a threat report issued in January said BlackSuit is a relatively new ransomware group with significant similarities to the Royal ransomware family, presenting "an increasing threat to the healthcare and public health sector."

Discovered in early May 2023, "BlackSuit’s striking parallels with Royal - the direct successor of the former notorious Russian-linked Conti operation - potentially place the group with one of the most active ransomware groups in operation today," HHS HC3 said.

BlackSuit primarily targets Linux systems and Windows and prevents victims from accessing their files by encrypting them, HHS HC3 said. BlackSuit operators also set up a data leak site as part of a double-extortion strategy to coerce victims into paying the ransom, the report says.

GHC-SCW did not immediately respond to Information Security Media Group's request for additional information about the incident, including the identity of the ransomware group that claimed credit for the attack and whether the organization paid a ransom.

"We have no indication that information has been used or further disclosed," GHC-SCW said in its breach notice. "To reduce the risk of this happening again, we have implemented enhanced security measures across all our systems and networks. This includes strengthening existing controls, data backup, user training and awareness, and other measures."

GHC-SCW is offering affected individuals 12 months of complimentary credit and identity monitoring.

Taking Action

While cyberthreats against healthcare sector entities persist and evolve, some organizations are taking actions to help bolster their defenses and better prepare their incident response, some experts said.

"Hospitals are thankfully improving their cybersecurity abilities and, in this case, the organization appears to have thwarted the criminals" in terms of attackers encrypting GHC-SWC's systems, said Jake Milstein, chief revenue officer at security firm Critical Insight.

"It's impossible to stop every attack, and GHC-SCW did the right thing here in limiting the impact of the attack," he said.

"Organizations need to be able to detect attacks that have gotten into the system to stop them from carrying out their full-scale attack," he said. When organizations have security operations centers monitoring the networks and catch attackers in the act, those security teams also are potentially protecting patients from harm caused by disrupted systems and services, Milstein said.

Employing a managed security service provider to provide 24/7/365 monitoring is indeed important, Walsh said. "Many organizations are more vulnerable during the evenings/nights, weekends, and holidays when they have a smaller or no IT staff working."

Walsh also said the use of data loss prevention to monitor and control the movement of confidential information across the network and endpoints and to cloud storage or cloud services can "identify and hopefully prevent unauthorized exfiltration of data."

Protecting Backups

In some cases, attackers target backup systems and data storage, which makes full restoration from ransomware and other attacks even more difficult and sometimes impossible.

"The single best ransomware risk mitigation control is to implement immutable backups with strong authentication, possibly with three elements, location of admin access, as well as token and username password," said Fred Langston, chief product officer at Critical Insight. "This virtually assures you will have uncorrupted backups to restore from."

Organizations also should store at least one set of backups offline, for confidential information in particular, said Walsh.

"This also helps when cloud-based backup systems have also been compromised or are not available," he said. Walsh said organizations should segment backup systems from the rest of the network to prevent ransomware from spreading to backup servers and storage.

"Regularly test backup and recovery processes to ensure their effectiveness. Train the staff responsible for backups on best practices," he said.

About the Author

Marianne Kolbasuk McGee

Marianne Kolbasuk McGee

Executive Editor, HealthcareInfoSecurity, ISMG

McGee is executive editor of Information Security Media Group's media site. She has about 30 years of IT journalism experience, with a focus on healthcare information technology issues for more than 15 years. Before joining ISMG in 2012, she was a reporter at InformationWeek magazine and news site and played a lead role in the launch of InformationWeek's healthcare IT media site.

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