The 0mega ransomware group has successfully pulled off an extortion attack against a company’s SharePoint Online environment without needing to use a compromised endpoint, which is how these attacks usually unfold. Instead, the threat group appears to have used a weakly secured administrator account to infiltrate the unnamed company’s environment, elevate permissions, and eventually exfiltrate sensitive data from the victim’s SharePoint libraries. The data was used to extort the victim to pay a ransom.

Likely First of its Kind Attack

The attack merits attention because most enterprise efforts to address the ransomware threat tend to focus on endpoint protection mechanisms, says Glenn Chisholm, cofounder and CPO at Obsidian, the security firm that discovered the attack.

“Companies have been trying to prevent or mitigate ransomware-group attacks entirely through endpoint security investments,” Chisholm says. “This attack shows that endpoint security isn’t enough, as many companies are now storing and accessing data in SaaS applications.”

The attack that Obsidian observed began with an 0mega group actor obtaining a poorly secured service account credential belonging to one of the victim organization’s Microsoft Global administrators. Not only was the breached account accessible from the public Internet, it also did not have multi-factor authentication (MFA) enabled — something that most security experts agree is a basic security necessity, especially for privileged accounts.

The threat actor used the compromised account to create an Active Directory user — somewhat brazenly — called “0mega” and then proceeded to grant the new account all the permissions needed to create havoc in the environment. These included permissions to be a Global Admin, SharePoint Admin, Exchange Admin, and Teams Administrator. For additional good measure, the threat actor used the compromised admin credential to grant the 0mega account with so-called site collection administrator capabilities within the organization’s SharePoint Online environment and to remove all other existing administrators.

In SharePoint-speak, a site collection is a group of websites within a Web application that share administrative…