Office 365 phishing campaign leverages Oracle and Amazon cloud services

Experts warn of a new sophisticated phishing scheme for stealing Office 365 credentials from small and medium-sized businesses in the U.S.

The new sophisticated phishing scheme was implemented by threat actors for stealing Office 365 credentials, it leverages both cloud services from Oracle and Amazon for their infrastructure.

The campaign has been active for more than half a year and targeted small and medium-sized businesses in the U.S. and Australia.

Threat actors used to compromise legitimate websites and used them as a proxy chain, This campaign also outstands for the abuse of legitimate services and websites for data exfiltration.

The phishing messages are fake notifications for voice messages and Zoom invitations that are created to trick victims into clicking an embedded link that finally lead the victim to the phishing page that was designed to steal login credentials.

Source Bleeping Computer

According to cybersecurity firm Mitiga, the threat actors used compromised accounts to send out phishing messages and used Amazon Web Services (AWS) and Oracle Cloud in the redirect chain.

“Once the link was clicked, the user is redirected through several proxies, including AWS load balancers, all the way to a legitimate but compromised website” Ofir Rozmann, threat intelligence at Mitiga told Bleeping Computer.

Before the victims land the final landing page, the user is redirected through several proxies, including AWS load balancers.

Most of the fake Office 365 login pages were hosted on Oracle Cloud computing service, but experts also observed the use of Amazon Simple Storage Service (Amazon S3).

Mitiga researchers discovered more than 40 compromised websites that were employed in this Office 365 phishing campaign.

The analysis of the HTML code for the fake Office 365 pages suggests that attackers opted for a phishing-as-a-service.

Based on the email addresses employed in this campaign, Mitiga researchers determined that the campaign mainly aimed at C-level executives at small and medium-sized businesses as well as major financial institutions.

Additional technical details about this campaign, along with Mitiga recommendations to avoid falling victim to these attacks are reported here.

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Pierluigi Paganini

(SecurityAffairs – hacking, Office 365)

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Pierluigi Paganini

Pierluigi Paganini is member of the ENISA (European Union Agency for Network and Information Security) Threat Landscape Stakeholder Group and Cyber G7 Group, he is also a Security Evangelist, Security Analyst and Freelance Writer. Editor-in-Chief at "Cyber Defense Magazine", Pierluigi is a cyber security expert with over 20 years experience in the field, he is Certified Ethical Hacker at EC Council in London. The passion for writing and a strong belief that security is founded on sharing and awareness led Pierluigi to find the security blog "Security Affairs" recently named a Top National Security Resource for US. Pierluigi is a member of the "The Hacker News" team and he is a writer for some major publications in the field such as Cyber War Zone, ICTTF, Infosec Island, Infosec Institute, The Hacker News Magazine and for many other Security magazines. Author of the Books "The Deep Dark Web" and “Digital Virtual Currency and Bitcoin”.