A damning report by the National Audit Office (NAO) has exposed some crucial flaws in the preparation of the NHS against cyber attack, following the WannaCry ransomware outbreak.

More than a third of NHS trusts in England were disrupted by WannaCry and at least 6,900 NHS appointments were cancelled as a result, though it is estimated as many as 19,000 appointments in total may have been affected. Over 600 computers at GP surgeries were locked and five hospitals had to direct ambulances elsewhere. NHS England said that no patient data had been compromised.

The WannaCry attack began on May 12 and quickly impacted organizations across 150 countries. The malware encrypted data on infected machines and demanded a ransom equivalent to £230 ($300). WannaCry spread using a computer exploit discovered by the NSA and leaked by a suspected Russian hacking group called The Shadow Brokers to bounce from machine to machine. As well as the NHS, many large, household names including Telefonica, FedEx and Renault were also affected.

The report from the NAO suggests that the NHS could have avoided the worst effects of the WannaCry attack by implementing “basic IT security” and said they should “get their act together to ensure the NHS is better protected against future attacks”.

Though the WannaCry outbreak had a significant impact, it was by all accounts an unsophisticated attack. Despite this it did expose serious shortcomings in NHS’ readiness and the overall health of its cyber security and we can all take something from these learnings.

The WannaCry attack could have been easily prevented if basic, fundamental security best practices were in place across all hospitals. These mistakes had wide reaching consequences, potentially affecting the lives of thousands of people.

What can you do you mitigate against a ransomware attack?

There are two main steps organisations must take to protect their systems from a ransomware attack: First, understanding your environment. By focusing on the finite detail of your operating systems, you can protect against the unknown. This includes having visibility and control of privileges and applications. Who is running and installing what? With what level of privilege? Removing local admin rights from end users is an essential part of any security strategy and prevents malware from spreading and accessing valuable data.

Second is making sure you are up to date with patches – a basic essential that is so often neglected.

It is crucially important to reduce the attack surface on your endpoints rather than relying on detection. For example, the leak from the NSA provided 20 different attack vectors, four of which were unknown to Microsoft. It is very easy to modify malware to bypass security techniques.

The NAO report is damning in its assessment of the NHS’ response plan and its imperative that lessons are learnt, and action is taken to mitigate the threat of similar attacks in the future.