WannaCry: hackers withdraw £108,000 of bitcoin ransom

Digital wallets linked to ransomware attack that crippled NHS hospitals are cleaned out, as law enforcement tries to track owners.

More than £108,000 in bitcoin paid by victims of the WannaCry ransomware attack, which crippled parts of the NHS as well as businesses in 150 countries worldwide, has been withdrawn from the digital wallets the funds were being held in.

Nearly three months after the ransomware struck computers, locking up data, demanding ransoms and causing chaos in hospitals and firms including Spain’s Telefonica and FedEx, a total of £108,953 worth of bitcoin was withdrawn. The money, presumably moved by the hackers, was taken from three bitcoin wallets associated with WannaCry, according to tracking firm Elliptic.

Victims of WannaCry were asked to pay between $300 (£228) and $600 in ransom with the promise of unlocking the files taken hostage by the malware, of which there were believed to have been around 230,000 computers worldwide. While law enforcement advised against paying the ransom, saying that it would only fund further acts of cyber criminality, victims appear to have done so in their hundreds to try and get their data back.

Between 24 July and 3 August, more than £18,000 in bitcoin was removed from the three wallets, with the remainder of the funds taken out in the early hours of Wednesday morning in seven batches worth between £15,000 and £21,000 each.

Since the attack, few anticipated that the ransom money would move. Part of the ransomware program gave the addresses of the digital wallets to victims and therefore law enforcement, which has been tracking them ever since. While bitcoin is considered a pseudonymous currency that cannot be tracked in the same way as traditional currencies, monitoring its movement is possible due to the way transactions are written into a distributed ledger called the blockchain.

That makes turning ill-gotten gains into traditional currencies harder to do anonymously. To do so requires the use of techniques such as a bitcoin mixer or tumbler, which intentionally confuses the trails of bitcoin transactions to protect the anonymity of the bitcoin owners.

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BTC-e, a major bitcoin exchange accused of laundering $4bn in bitcoin since it emerged in 2011, was shut down in July after the “internationally sought criminal mastermind” behind it was arrested in Greece, which will make anonymously turning the ransom bitcoins into cash even harder.

Elliptic co-founder Tom Robinson told CNBC: “We believe some of these funds are being converted into Monero, a privacy-focused cryptocurrency.”

The funds may also be used to purchase goods and services directly in bitcoin on the dark web, adding another layer of difficulty to tracking the wallets’ owners.

The ransomware attack, which has been linked to North Korea, is thought to be at least partially politically driven rather than an outright move for money. As a piece of ransomware designed to extort users, WannaCry was a victim of its own success hitting large firms and spreading across networks using holes in Windows XP and Windows 7 to propagate far and wide.

But while ransomware targeting business and institutions causes large amounts of disruption, such as reducing some NHS hospitals to emergency care only and forcing them back to pen and paper, businesses are unlikely to pay the ransom.

Where individual home users may not have backups of their data that can be easily restored, and therefore are more likely to pay the ransom to try and get their files back, most businesses will have routine backups and can restore the majority of files relatively easily once the infection has been purged.