Microsoft has raised its voice of concern over the issue of increasing number of consent phishing (aka OAuth phishing) attacks targeting remote workers in the past few months. An APT known as TA2552 has been spotted using OAuth2 or other token-based authorization methods to access Office 365 accounts, in order to steal users’ contacts and mail.
OAuth is an open standard for access delegation, commonly used as a way for people to sign into services without entering a password. The most visible example might be the ‘Sign in with Google’ or ‘Sign in with Facebook’ that many websites use in lieu of asking visitors to create a new account. Consent phishing (also known as OAuth phishing) is an application-based attack variant where the attackers attempt to trick targets into providing malicious Office 365 OAuth apps (web apps registered by the attackers with an OAuth 2.0 provider) with access to their Office 365 accounts.
With the help of the compromised Office 365 accounts, the attackers gain access to victims’ emails, files, contacts, as well as sensitive information and resources stored on corporate SharePoint document management/storage systems and/or OneDrive for Business cloud storage spaces.
In order to avoid consent phishing, Microsoft customers must check if they have given the access to their personal details to any consent apps or services. Organizations must use publisher verified apps and educate its employees to spot consent phishing tactics in order to avoid such phishing attacks