Despite the main infections taking place two and half years ago, a large number of computers remain vulnerable to the WannaCry ransomware.

Speaking to Infosecurity at the Virus Bulletin 2019 conference in London, Sophos security researcher Chet Wisniewski said that there are large numbers of businesses who did not apply the patches, released in March and after the infection in May 2017, so machines still remain vulnerable. “That’s what surprised me, with the amount of hype and the amount of news around that vulnerability, it shows that even standing on the rooftop and lighting your hair on fire is not going to be enough for people to take action,” he said.

“The good news is that there is an accidental vaccination which means that the good people won’t get infected with it,” he said. He explained that a version of WannaCry drops a payload, but that payload is currently corrupted and if another infection is attempted, if that file is detected at all, the infection will not take place.

“Fortunately, all of these copies of WannaCry we’re seeing are neutered,” he added. “It’s not hurting anyone, it’s just spreading around and making a lot of noise.”

Wisniewski went on to say that people are still not realizing that “these weaponized exploits are really dangerous, and BlueKeep has been an interesting trial of this.” In that case, he said that wormable exploits are typically published within hours, but in the case of BlueKeep that has only been added to Metasploit and other companies are using it as a penetration testing tool.

“If people have not patched since 2017, if a BlueKeep publicly exploitable worm was released, instantly millions of machines would be impacted again, and we would be in the same boat as when WannaCry was spreading around,” he said. “Every single one of those machines would be vulnerable as they have not been patched in two years, not to mention all of those that have been patched since.”