Listen to this Post
Introduction:
In the modern cloud-centric enterprise, protecting privileged accounts and sensitive data repositories is paramount. Conditional Access in Microsoft Entra ID serves as the core policy engine for a Zero Trust architecture, enabling security teams to enforce granular, context-aware authentication requirements. This article provides a technical deep dive into implementing Authentication Contexts to secure Privileged Identity Management (PIM) and SharePoint sites with step-up authentication.
Learning Objectives:
- Understand the architecture and deployment of Authentication Contexts and Continuous Access Evaluation (CAE).
- Learn to configure granular Conditional Access policies for PIM activation and sensitive resource access.
- Master the technical commands and scripts for automating and validating the security posture of your Entra ID environment.
You Should Know:
1. Enabling Continuous Access Evaluation (CAE) with PowerShell
Continuous Access Evaluation provides real-time enforcement of Conditional Access policies by reacting to critical events like user disablement or password change instantly, rather than waiting for token expiration.
Connect-MgGraph -Scopes "Policy.ReadWrite.ConditionalAccess", "Application.Read.All"
$params = @{
"@odata.type" = "microsoft.graph.continuousAccessEvaluationPolicy"
DisplayName = "Contoso CAE Policy"
Description = "Default organizational CAE policy"
State = "enabled"
}
Update-MgPolicyContinuousAccessEvaluationPolicy -BodyParameter $params
Step-by-step guide:
- Install the Microsoft Graph PowerShell SDK (
Install-Module Microsoft.Graph). - Connect to Graph API with the required scopes as shown.
- The `$params` hashtable defines the CAE policy parameters. Setting `State` to “enabled” is crucial.
- Executing `Update-MgPolicyContinuousAccessEvaluationPolicy` applies this configuration to your tenant. CAE works with compatible applications (e.g., Office web apps) to immediately revoke access upon detecting risk.
2. Configuring an Authentication Context for PIM Activation
Authentication Contexts allow you to define a specific security requirement, such as requiring a compliant device and phishing-resistant MFA to activate a privileged role.
$authContext = New-MgIdentityConditionalAccessAuthenticationContext -Id "PIM_StepUp_Requirement" -DisplayName "PIM Role Activation: Requires Compliant Device + MFA"
Step-by-step guide:
- This command creates a new Authentication Context object with the ID
PIM_StepUp_Requirement. - This ID is then referenced in a Conditional Access policy that targets “Privileged Identity Management” as a cloud app.
- In the CA policy, grant access only if the requirement “Require authentication context” is met, selecting the created context. The policy should then require the chosen grant controls (MFA, compliant device).
-
Applying an Authentication Context to a SharePoint Site via PowerShell
Sensitive SharePoint sites can be protected by requiring a specific Authentication Context for access, ensuring step-up authentication.
Register-PnPManagementShellAccess Connect-PnPOnline -Url https://<YourTenant>.sharepoint.com/sites/<YourSite> -Interactive Set-PnPSite -AuthenticationContextName "PIM_StepUp_Requirement"
Step-by-step guide:
- Use the PnP PowerShell module to interact with SharePoint Online (
Install-Module -Name PnP.PowerShell).
2. Connect to your target SharePoint site.
- The `Set-PnPSite` cmdlet applies the Authentication Context named “PIM_StepUp_Requirement” to the entire site collection. Now, any user trying to access this site will trigger the associated Conditional Access policy.
-
Audit User Sign-Ins with Filter for Authentication Context
Monitoring and troubleshooting are critical. This Kusto Query Language (KQL) query for Azure Monitor Logs filters sign-in logs for events triggered by a specific Authentication Context.
SigninLogs | where AuthenticationDetails has "PIM_StepUp_Requirement" | project TimeGenerated, UserDisplayName, AppDisplayName, IPAddress, ResultType, AuthenticationDetails | sort by TimeGenerated desc
Step-by-step guide:
- Navigate to Azure Monitor Logs in the Azure Portal.
2. Select the `SigninLogs` table.
- Run this query to find all sign-in attempts where the specified Authentication Context was required. This is essential for verifying policy application and investigating access attempts.
-
Leverage Microsoft Graph API to List Conditional Access Policies
Automating security audits ensures consistency. This Bash script uses curl to fetch all Conditional Access policies via the Microsoft Graph API, parsing the JSON output for critical details.
ACCESS_TOKEN="$(az account get-access-token --resource-type ms-graph --query accessToken -o tsv)"
curl -s -H "Authorization: Bearer $ACCESS_TOKEN" -H "Content-Type: application/json" "https://graph.microsoft.com/v1.0/identity/conditionalAccess/policies" | jq '.value[] | {displayName, state, grantControls, conditions}'
Step-by-step guide:
1. Prerequisites: Azure CLI (`az`) and `jq` installed.
- The `az account get-access-token` command retrieves a fresh access token for the Microsoft Graph resource.
- The curl command calls the Graph API endpoint for Conditional Access policies, and the `jq` utility parses the JSON response to extract the policy name, state, and controls for review.
-
Detect Risky PIM Activations with a Sentinel Analytic Rule
Proactive threat hunting requires detecting anomalies. This KQL query for a Microsoft Sentinel analytics rule looks for PIM activations that occur from an unfamiliar location shortly after a risky sign-in.
AuditLogs
| where OperationName == "Elevate access (role activation)"
| join (SigninLogs | where RiskLevelDuringSignIn has_any ("medium", "high")) on $left.Identity eq $right.Identity
| where TimeGenerated between (SigninLogs.TimeGenerated .. 10m)
| project TimeGenerated, UserPrincipalName, RoleDisplayName, IPAddress, RiskLevelDuringSignIn
Step-by-step guide:
- This query joins the `AuditLogs` (for the PIM activation event) with the `SigninLogs` (for risky sign-ins).
- The `between` operator filters for activations that happen within 10 minutes of the risky sign-in.
- Use this query as the foundation for a custom analytics rule in Microsoft Sentinel to generate security alerts for suspicious privilege escalation.
What Undercode Say:
- Granularity is the Foundation of Zero Trust. Authentication Contexts move security beyond simple app-level policies, enabling micro-segmentation of access within applications themselves. This drastically reduces the attack surface.
- Automation is Non-Negotiable. Manually checking the configuration of hundreds of policies and sites is unreliable. The provided Graph API and PowerShell scripts are essential for continuous compliance auditing and configuration drift detection.
The technical implementation showcased here represents a significant evolution beyond basic Conditional Access. By binding PIM activation and sensitive data access to specific, strong authentication contexts, organizations can effectively implement step-up authentication and achieve a true Just-In-Time (JIT) and Just-Enough-Access (JEA) model. The provided commands are not just examples; they are production-ready tools for building, auditing, and monitoring this advanced security framework.
Prediction:
The sophistication of identity-based attacks will continue to escalate, directly targeting the gaps between standard MFA and privileged access workflows. The manual, app-level Conditional Access policies of today will become obsolete. Within two years, we predict the mass adoption of automated, AI-driven identity security systems that use contextual signals like authentication contexts and CAE to dynamically adjust access privileges in real-time, not just at initial login. This will create a self-defending identity environment where access is continuously validated, rendering stolen cookies and tokens useless against critical resources.
🎯Let’s Practice For Free:
IT/Security Reporter URL:
Reported By: Ewelinapaczkowska Conditionalaccess – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
