A newly discovered vulnerability, dubbed “G-Door,” allows malicious actors to circumvent Microsoft 365 security measures by exploiting unmanaged Google Docs accounts. This security flaw poses a significant threat to organizations relying on Microsoft 365’s Conditional Access (CA) policies for protection.
According to Potsolutions the G-Door vulnerability stems from the ability to create personal or workspace Google accounts using a company’s domain name. These unmanaged accounts can then access third-party applications, bypassing Microsoft 365’s security controls.
G-Door Vulnerability Security Risks
- Circumventing Conditional Access: Users or attackers can create Google accounts with corporate email addresses, sidestepping crucial security measures like multi-factor authentication (MFA), device compliance checks, and geolocation restrictions.
- Lack of Visibility: Activity from these unmanaged accounts doesn’t appear in Microsoft 365 Admin Center logs, hindering incident response and anomaly detection.
- Data Exposure: Sensitive information stored in Google Drive or created in Google Docs isn’t subject to corporate Data Loss Prevention (DLP) or Azure Information Protection (AIP) policies.
- Persistent Access: Attackers who compromise a Microsoft 365 account can create a separate Google identity, maintaining access to third-party apps even after the original credentials are revoked.
- Inadequate Offboarding: Employees may retain unauthorized access to connected apps or data repositories through unmanaged Google accounts after leaving the company.
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Users can easily create personal Google accounts or sign up for the free Google Docs Essentials Starter plan using their company email addresses.
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This process requires no administrative approval and can be completed in minutes, giving users an unmanaged Google identity associated with the organization’s domain, reads the report.
The G-Door vulnerability undermines several key security features of Microsoft 365:
- Conditional Access policies become ineffective for these unmanaged accounts.
- Device compliance and geolocation restrictions can be bypassed.
- Data protection measures and legal compliance efforts are compromised.
- Group-based access controls in Azure AD (Entra) can be circumvented.
To protect against the G-Door vulnerability, organizations should:
- Implement strict domain verification processes for Google Workspace.
- Regularly audit and manage unmanaged accounts associated with the company domain.
- Enhance user education about the risks of creating personal accounts with work email addresses.
- Consider implementing additional third-party security solutions to monitor and control access across multiple cloud platforms.
As organizations increasingly rely on cloud-based productivity suites, addressing vulnerabilities like G-Door becomes crucial for maintaining a robust security posture. IT administrators and security professionals must remain vigilant and adapt their strategies to protect against these emerging threats.
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