Barts Health NHS Trust has ruled out a ransomware attack on its systems today, but confirmed a cyber attack has potentially put patient data at risk.
The hospital trust sent staff an email this morning, warning that engineers were investigating a ransomware attack, according to the Health Service Journal (HSJ).
However, a spokeswoman subsequently told IT Pro: "Earlier this morning ransomware was a possibility, however now at this later stage in our investigation we don't believe ransomware is involved."
On the other hand, the trust has not been able to establish what kind of cyber attack it has suffered, and has had to take some drives and systems offline during an ongoing investigation.
"We are going through [our systems] and we are making things accessible as we do that," the spokeswoman told IT Pro. "We are having to go through everything to make sure it's not hiding anywhere."
So far, the trust has established that the Cerner Millennium patient administration system and the clinical system used for radiology are not affected.
HSJ reported that the cyber attack affected thousands of files that are stored on computers running the out-of-support Windows XP operating system.
Nine in 10 NHS trusts still rely on the OS, despite Microsoft ending support for it in April 2014, according to a Freedom of Information (FoI) request conducted in October 2016, and published in December.
Another FoI last year suggested cyber criminals had targeted at least 28 NHS trusts with ransomware in the previous 12 months, seeking to lock access to patient data until the trusts paid a fee. NHS Digital, the body that oversees cybersecurity for the health service, said no ransom was ever paid and no data was lost.
A ransomware attack on Northern Lincolnshire and Google NHS Foundation Trust's network in November led to the cancellation of 2,800 appointments, after it severely affected the trust's IT systems for four days.
The Barts Health NHS Trust spokeswoman said: "We are urgently investigating this matter and have taken a number of drives offline as a precautionary measure. We have tried and tested contingency plans in place and are making every effort to ensure that patient care will not be affected."
