A vast botnet of over 130,000 compromised devices is now attacking Microsoft 365 accounts worldwide. A botnet is a network of computing devices that have been surreptitiously taken over by hackers and are being controlled remotely without the owners’ knowledge.

Microsoft 365 accounts are suffering from ‘password spray attacks’ by the botnet. This involves mass attempts to use large numbers of common passwords to infiltrate users’ Microsoft accounts, targeting basic authentication procedures and thereby bypassing multi-factor authentication.