Broken records are rarely a positive thing in the cybersecurity world. Earlier this month, in a matter of hours, thousands of people who had never heard of ransomware had become uncomfortably familiar with the largest ransomware attack in history.
Over 70 countries have been hit with WannaCry. At its core, it works in the same way as any other ransomware attack; it encrypts the contents of infected machines – in this case, those running a particular version of Microsoft Windows – and demands bitcoin payment in return for unlocking the file system and restoring access to the encrypted files.
But what has made WannaCry so successful? And what can it teach organisations about preparing better for the next generation of attacks?
How did this happen?
On April 14th, 2017, a group called the Shadow Brokers dumped a set of internal software tools from the NSA. These are tools that nation states create or purchase to exploit weaknesses in standard software used by individuals and corporations worldwide – all part of the ongoing digital arms race.
Somehow – and it’s unclear exactly how – the Shadow Brokers had managed to access some of these tools and posted them freely online – think of it as someone making off with weapons-grade plutonium and just giving it away.
Three groups of exploits were included in the dump. One group was a collection of documents and top secrete PowerPoint presentations. One group related to data from the SWIFT payment network – you might remember the extraordinary Bangladesh Bank heist from last year, which exploited weaknesses in the same system.
Finally – and most interestingly – the last group consisted of a package of exploits for Windows machines. Some of these exploits had never been seen before, and cybersecurity researchers immediately braced themselves for a new spate of attacks that capitalised on them.
Enter WannaCry, which uses an exploit from the trove codenamed ETERNALBLUE & DoublePulsar to rapidly infect Windows machines on a network.
Microsoft actually released MS17–010, a security update to fix that particular vulnerability, before the NSA hacking tools were released to the public. However, as per standard commercial practice, the update was only released for the firm’s currently supported operating systems. Anyone running an older operating system – or being a bit lackadaisical about their software updates – remained unprotected.
The kill switch
However, as the infection broke, a “kill switch” was discovered. A kill switch is often used to ensure that the creator has some control after the infection is out in the wild. At the very least, they typically want to ensure they can control it while they are actively creating or testing the malware so they do not demolish their own computers. In this instance, the kill switch was discovered to be a website that the ransomware would check before it activated itself on an infected machine. Security researchers quickly purchased the domain and it stopped computers that had internet access from further infection. Meanwhile, Microsoft worked on releasing patches for the older, unprotected operating systems to stem the tide.
Problem averted, then? Not really. New versions of the ransomware have already been developed and released – and these feature different kill switches – or even no kill switches at all.
Back to basics
The process of breaking through an organisation’s firewall requires an initial backdoor into the system – and here, WannaCry used the oldest trick in the book. Phishing emails got the worm onto “patient zero” within a network – because too many organisations still have woefully inadequate email protections in place.
DMARC, for example, a tool that detects and prevents email spoofing, has been described by the National Cyber Security Centre (NSCS) as a fundamental security protection. Yet a recent review of domains belonging to around 200 NHS authorities and trusts revealed that just one has implemented DMARC – and even that is in the initial ‘reporting’ mode and receives no active protection from it.
In short, our hospitals are not only running unpatched, unsupported installations of the Windows operating system, they have practically no defence against other email-borne threats.
WannaCry and its newly forming variants are still spreading and organisations need to clean up. Some variants appear to be dormant but replicating, so it is safe to say that the true extent of the problem, as yet, is underreported.
US-CERT, the American Computer Emergency team, has been updating an alert on WannaCry and provides a section for Solutions and Recommended Steps for Prevention. It has made a number of recommendations – two of which, in my view, stand out as basic, actionable measures. First, upgrade your system with the latest Microsoft patches to stop the spread. Second, implement technology such as DMARC to prevent email spoofing and start reducing exposure to phishing.
Traditionally, DMARC has been complicated and expensive to deploy – potentially why the NHS has been so slow to get on board – but new cloud-based services are making it both faster and more cost-effective to implement.
No magic bullet
Even the US-CERT recommendations are by no means a magic bullet defence against threats like WannaCry. The reality is that email protection and recently patched operating systems are just two parts of a complex system of security tools and processes that need to be in play within organisations today.
Cybersecurity is now part of the cost of doing business, not just a procedure to be invoked when things go wrong. It’s the difference between treatment and vaccination — when possible, prevention is far preferable to cleaning up after the epidemic. This should be a wake-up call for businesses, governments, regulators and ordinary citizens alike.
"Business should implement technology such as DMARC to prevent email spoofing and start reducing exposure to phishing"
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