In January 2017 we became informed of a successful attack against the largest NHS trust in England. The media came to conclusion that it was a ransomware attack, which are usual these days. However, the NHS officials disputed these assumptions.
Some new facts were publicly disclosed on March 1 during the NHS board meeting. The original report (available here) says that the attack was carried out by “a new virus not seen previously”. Here is the original quote from the report:
An IT virus had affected the Trust’s networks during January 2017. It was confirmed that this had affected all sites, except Whipps Cross but that the response had been effective and the Trust had swiftly returned to business as usual. The virus had affected pathology systems (requiring the temporary use of manual systems), but no other IT systems used to deliver clinical care. A serious incident investigation was under way and further details would be shared once this had concluded. The Deputy Chief Executive noted some inaccuracies in media reporting about this incident, confirming that this virus had not been a ransomware attack and that the Trust’s patient information systems had not been hacked or otherwise compromised (with no patient data stolen or at risk). He explained that the Trust’s antivirus software had been up to date and that this had been a new virus not seen previously. A ‘patch’ had been issued globally within 8 hours, protecting other organisations from this virus. He thanked teams for their hard work and support to maintain business as usual standards in difficult circumstances. The Chief Executive noted that she had visited Pathology departments to thank them for their work during the affected weekend to oversee contingency arrangements.
Based on this report and other statements, made previously to the media, we may conclude that the only security mechanism in place was a signature-based antivirus software, which did not have signature for this particular malware variant/sample. A little bit of googling revealed that NHS computers use Windows XP operating system, which is no longer supported by Microsoft. This explains why they have to rely on antivirus only.
The attack affected the following hospitals: the Royal London, St Bartholomew’s, Mile End and Newham. Since the IT department had to disconnect network shares and some drives, the malware in question is most likely to be a worm spreading via SMB shares.
Yesterday some media reported that a zero-day vulnerability was used for this attack. We believe that this is a FALSE statement. To avoid any speculations in the future, we do not believe this was a targeted attack either. Most likely this was just a random infection with a random malware. The kind of infection we see on a daily basis in organizations with poorly implemented security controls.