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NZ battens down the hatches as global ransomware attack spreads

“Biggest ransomware outbreak in history” hits 99 countries across four continents.

New Zealand is bracing itself for a potentially huge cyber attack following a spate of breaches across the world, as the government battens down the hatches in preparation for the “biggest ransomware outbreak in history”.

Following a weekend of chaos across the globe, more than 75,000 attacks have been reported across 99 countries, with the UK National Health Service (NHS) crippled, the Russian government infected and the Spanish telecommunications sector at a standstill.

With Europe bearing the brunt of the attack, German railways also screeched to a halt, while US-based courier FedEx Corp suffered interference as the ransomware also spread to Asia and South America.

Known as WannaCry and variants of that name, the malicious software locked computers in thousands of locations worldwide, demanding US$300 ransom per machine to be paid in cryptocurrency Bitcoin to unlock devices.

“New Zealand cyber security authorities are aware a significant international ransomware campaign - WannaCry,” the Government Communications Security Bureau said via a spokesperson on 13 May.

At this stage, no organisations locally have reported any incidents relating to the breach, with the National Cyber Security Centre (NCSC) currently working with the newly established CERT NZ to help combat any potential future attacks.

“The NCSC is taking steps to help increase the resilience of New Zealand’s nationally significant systems,” a spokesperson said. “These steps include technical measures and provision of mitigation advice.

“The NCSC is aware that the ransomware exploits a known vulnerability in Windows operating systems and has previously provided advice to it’s customers on addressing this vulnerability

Ransom demand screen displayed by WannaCry Trojan (Image - Symantec Security Response)
Ransom demand screen displayed by WannaCry Trojan (Image - Symantec Security Response)

“We are also working with CERT NZ to provide information on how individuals, small businesses and operators of larger systems can reduce their vulnerability to ransomware attacks.”

What is WannaCry?

The hackers are believed to have used a stolen tool developed by the US National Security Agency, which was released to the world by a group known as the Shadow Brokers in April.

“The attack vector has all the hallmarks of a traditional computer worm,” CrowdStrike vice president of intelligence Adam Meyers told Reseller News.

“We’ve not seen a large-scale ransomware campaign that uses self-propagating technique at this scale before, which makes it really unique.”

Meyers said targeting was likely in bulk, via massive phishing campaigns delivering .zip archives with themes such as fake invoices, job offers, security warnings, undelivered email.

“Once an infection takes place, Wana encrypts victim files using the AES-128 cipher, and demands a Bitcoin ransom of increasing value as time passes,” Meyers explained.

“Files encrypted by Wana are appended with a file extension of .wncry. Observed ransom demands require victims to pay either US$300 or US$600 worth of Bitcoin for a decryption key.”

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According to Meyers, early analysis of the worm is that it is taking advantage of a very recent Microsoft Windows exploit called EternalBlue, which is the enabler for how files get shared.

“Swift action to patch against this update is critical,” Meyers added. “Whilst ensuring that back-up data files are disconnected from the core network, as this ransomware has the potential to encrypt back-up files.”

Early reports show the malware originating in Europe and impacting healthcare organisations, hospitals, surgeries, telecommunication systems as well as gas and electricity utilities.

“The group behind the attack does not appear to be picky about the nation or sector it is targeting,” Meyers added.

After WannaCry encrypts data files and asks users to pay a US$300 ransom in Bitcoins, the ransom note indicates that the payment amount will be doubled after three days.

This is what the victim’s wallpaper is changed to following the breach (Image - Avast Software)
This is what the victim’s wallpaper is changed to following the breach (Image - Avast Software)

If payment is not made after seven days, the encrypted files will be deleted.

“WannaCry has the ability to spread itself within corporate networks, without user interaction, by exploiting a known vulnerability in Microsoft Windows,” a Symantec Security Response statement read.

“Computers which do not have the latest Windows security updates applied are at risk of infection.”

While the breaches appear to be linked, researchers believe it may not be a coordinated attack on specific targets, a theory backed up by UK Prime Minister Theresa May.

“This is not targeted at the NHS, it’s an international attack and a number of countries and organisations have been affected,” May said on 12 May.

Increased activity of the ransomware strain was first globally reported at 8am Central European Time (CET) on 12 May, with attacks then rapidly increasing across the world during the next 24 hours.

“We saw the first version of WanaCrypt0r in February and now the ransomware is available in 28 different languages, from languages like Bulgarian to Vietnamese,” Avast Software threat intelligence analyst Jakub Kroustek said.

"The ransomware changes the affected file extension names to “.WNCRY”, so an infected file will look something like: original_name_of_file.jpg.WNCRY, for example. The encrypted files are also marked by the “WANACRY!” string at the beginning of the file.”

According to Kroustek, the ransomware drops the following ransom notes in a text file and after demanding the bitcoin ransom, the victim’s wallpaper is changed.

“This attack once again proves that ransomware is a powerful weapon that can be used against consumers and businesses alike,” Kroustek said.

“Ransomware becomes particularly nasty when it infects institutions like hospitals, where it can put people’s lives in danger.”

A security researcher may have helped stop the spread of the ransomware, through the deployment of a kill switch solution. The kill switch appears to work like this - if the malicious program can’t connect to the domain, it’ll proceed with the infection. If the connection succeeds, the program will stop the attack.
(Updated - 13 May at 2:18pm)