Over recent months, the cybersecurity industry has seen a huge increase in malicious attackers exploiting the networks of Microsoft and Google to host and deliver threats through Office 365 and Azure.
The actors who are at risk are quickly moving towards cloud-based business services during the pandemic by concealing themselves behind omnipresent, trustworthy services from Microsoft and Google to make their email phishing scams appear legitimate; and it works.
In particular, during the first three months of the year 2021, researchers discovered that 7 million malicious e-mails were sent from Microsoft's 365, and also that 45 million were transported from Google's network. The Proofpoint team said that cyber-criminals had been able to send phishing e-mails and host attacks with Office 365, Azure, OneDrive, SharePoint, G-Suite, and Firebase.
“The malicious message volume from these trusted cloud services exceeded that of any botnet in 2020, and the trusted reputation of these domains, including outlook.com and sharepoint.com, increases the difficulty of detection for defenders,” the report, issued on Wednesday, explained. “This authenticity perception is essential, as email recently regained its status as the top vector for ransomware; and threat actors increasingly leverage the supply chain and partner ecosystem to compromise accounts, steal credentials and siphon funds.”
Proofpoint estimated that 95% of cloud account organizations had been attacked, and more than half of them succeeded. Additionally, more than 30% of those organizations were compromised.
Once attackers have access to passwords, they can easily enter or exit several services and send out more, persuasive phishing emails.
Proofpoint offered many examples of projects behind Microsoft and Google that tried to scam users to give up or deliver their details.
Attackers exploited Gmail to host another operation throughout March, that provided them with the message of the fake benefits together with a Microsoft Excel attachment, that delivered The Trick Bank Trojan to steal credentials whenever macros were activated.
Another Gmail-hosted February attack seeks to persuade users to use their passwords for accessing zip-on MS Word documents. Upon opening, Xorist ransomware has been delivered.
The use of Gmail and Microsoft by attackers to give their emails a patina of credibility is part of a broader trend: threats are developing increasingly persuasive appeals.
“Our research demonstrates that attackers are using both Microsoft and Google infrastructure to disseminate malicious messages and target people, as they leverage popular cloud-collaboration tools,” the Proofpoint report added. “When coupled with heightened ransomware, supply chain, and cloud account compromise, advanced people-centric email protection must remain a top priority for security leaders.”
