The attack was carried out against a hospital in Västra Götaland, but it remains unclear if any patient information was leaked, wrote the Expressen newspaper.
When the hospital’s servers were hacked on August 21st, hospital IT staff were met with a red warning text reading: “We will not abandon Julian Assange” together with the name “Anonymous”.
The hacker attack put information about hundreds of thousands of patients at risk, including files dating between the early nineties to 2009.
However, regional healthcare system IT head Göran Ejbyfeldt explained that many questions remain unanswered following the attack.
“I repeat: they were able to access the servers. We cannot be sure if they have got into the data,” he told Expressen.
“When we found out what was happening we closed the system down completely.”
The information possibly breached in the attack included names, addresses, and even which section of the hospital patients were treated, but not any medical records.
Patients whose data was at risk were from Trollhättan, Vänersborg and Uddevalla, all towns in western Sweden.
In early October, Anonymous took responsibility for a series of other cyber attacks on Swedish state interests.
The case involving the hospital has now been reported to police as hacking.