Threat actors are misusing OAuth applications as an automation tool in financially motivated attacks. OAuth is an open standard for token-based authentication and authorization that enables applications to get access to data and resources based on permissions set by a user. Threat actors compromise user accounts to create, modify, and grant high privileges to OAuth applications that they can misuse to hide malicious activity. The misuse of OAuth also enables threat actors to maintain access to applications even if they lose access to the initially compromised account. In attacks observed by Microsoft Threat Intelligence, threat actors launched phishing or password spraying attacks to compromise user accounts that did not have strong authentication mechanisms and had permissions to create or modify OAuth applications. The threat actors misused the OAuth applications with high privilege permissions to deploy virtual machines (VMs) for cryptocurrency mining, establish persistence following business email compromise (BEC), and launch spamming activity using the targeted organization’s resources and domain name. Microsoft continuously tracks attacks that misuse of OAuth applications for a wide range of malicious activity. This visibility enhances the detection of malicious OAuth applications via Microsoft Defender for Cloud Apps and prevents compromised user accounts from accessing resources via Microsoft Defender XDR and Microsoft Entra Identity Protection. In this blog post,…Read More