WannaCry ransomeware worm has majorly affected the running of Microsoft's Windows 7, security firms suggest.
Security firms like Kaspersky Lab and BitSight has reported that more than 97% and 66% respectively of the infections were found on the older versions.
WannaCry malware till now has infected more than 200,000 computers around the world.
A researcher from Kaspersky Lab, Costin Raiu said that infections of XP by WannaCry were "insignificant."
According to the figures showed by Kasperksy lab, the most infected version of Windows 7 was the x64 edition, which is widely used around the world.
Microsoft had issued a patch in March that blocked the vulnerability exploited by the WannaCry malware, but most of organisations failed to apply a patch.
Spanish telecoms firm Telefonica, French car-maker Renault, German rail firm Deutsche Bahn, logistics firm Fedex, Russia's interior ministry and 61 NHS organisations were all affected by WannaCry.
But, there is no reports that anyone has paid to get their data restored.
Adam McNeil, a senior malware analyst at Malwarebytes, said "the worm was primed to look for machines vulnerable to a bug in a Microsoft technology known as the Server Message Block (SMB)."
"The attackers initiated an operation to hunt down vulnerable public facing SMB ports and, once located, used the newly available SMB exploits to deploy malware and propagate to other vulnerable machines within connected networks," he wrote.
Security firms like Kaspersky Lab and BitSight has reported that more than 97% and 66% respectively of the infections were found on the older versions.
WannaCry malware till now has infected more than 200,000 computers around the world.
A researcher from Kaspersky Lab, Costin Raiu said that infections of XP by WannaCry were "insignificant."
According to the figures showed by Kasperksy lab, the most infected version of Windows 7 was the x64 edition, which is widely used around the world.
Microsoft had issued a patch in March that blocked the vulnerability exploited by the WannaCry malware, but most of organisations failed to apply a patch.
Spanish telecoms firm Telefonica, French car-maker Renault, German rail firm Deutsche Bahn, logistics firm Fedex, Russia's interior ministry and 61 NHS organisations were all affected by WannaCry.
But, there is no reports that anyone has paid to get their data restored.
Adam McNeil, a senior malware analyst at Malwarebytes, said "the worm was primed to look for machines vulnerable to a bug in a Microsoft technology known as the Server Message Block (SMB)."
"The attackers initiated an operation to hunt down vulnerable public facing SMB ports and, once located, used the newly available SMB exploits to deploy malware and propagate to other vulnerable machines within connected networks," he wrote.