“In logs reviewed by Volexity, initial device registration was successful shortly after interacting with the attacker. Access to email data occurring the following day, which was when UTA0355 had engineered a situation where their 2FA request would be approved,” Volexity researchers say. Volexity researchers say that once the device registered, they had to convince the target to approve the two-factor authentication (2FA) request to be able to access the victim's email. Cybersecurity company Volexity observed this activity since early March, right after a similar operation, reported in February by Volexity and Microsoft, that used Device Code Authentication phishing to steal Microsoft 365 accounts. Russian threat actors have been abusing legitimate OAuth 2.0 authentication workflows to hijack Microsoft 365 accounts of employees of organizations related to Ukraine and human rights. The purpose is to convince potential victims to provide Microsoft authorization codes that give access to accounts, or to click on malicious links that collect logins and one-time access codes. This final step gives the attacker a token to access the victim’s information and emails, but also a newly registered device to maintain unauthorized access for a longer period. UTA0352 may share instructions to join the meeting in the form of a PDF file along with a malicious URL crafted to log the user into Microsoft and third-party apps that use Microsoft 365 OAuth workflows.
This Cyber News was published on www.bleepingcomputer.com. Publication date: Thu, 24 Apr 2025 20:25:12 +0000