Use cloud authentication

Overview

An on-premises federation server introduces a critical attack surface by serving as a central authentication point for cloud applications. Threat actors often gain a foothold by compromising a privileged user such as a help desk representative or an operations engineer through attacks like phishing, credential stuffing, or exploiting weak passwords. They might also target unpatched vulnerabilities in infrastructure, use remote code execution exploits, attack the Kerberos protocol, or use pass-the-hash attacks to escalate privileges. Misconfigured remote access tools like remote desktop protocol (RDP), virtual private network (VPN), or jump servers provide other entry points, while supply chain compromises or malicious insiders further increase exposure. Once inside, threat actors can manipulate authentication flows, forge security tokens to impersonate any user, and pivot into cloud environments. Establishing persistence, they can disable security logs, evade detection, and exfiltrate sensitive data.

Remediation

• Migrate from federation to cloud authentication like Microsoft Entra Password hash synchronization (PHS).

Run it

The check runs as part of the whole assessment, with the ZeroTrustAssessment module installed:

Install-Module ZeroTrustAssessment -Scope CurrentUser
Connect-Maester
Invoke-Maester -Pack ZTA -SkipBuiltIn

Leave out -SkipBuiltIn to run Maester’s own checks in the same run.

About this check

Severity	High
Effort to fix	High
Impact on users	High
Pillar	Identity
Category	Access control
Product	Entra ID
Feature	Hybrid identity
Area	Authentication
ATT&CK	T1606.002 SAML Tokens, T1484.002 Trust Modification
Licence	P1
Tenant	Workforce

Product, feature, area and ATT&CK are Maester’s: the assessment does not record them, so Maester keeps them in the pack’s taxonomy.json.

A Microsoft check, part of the Zero Trust Assessment pack. Text from ZeroTrustAssessment 3.1.0, © Microsoft, MIT licence.