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Introduction
A critical scope overreach vulnerability was recently identified in the Microsoft Entra Agent Identity Platform, allowing the newly introduced Agent ID Administrator role to hijack arbitrary service principals across an entire tenant and escalate privileges. Because agent identities are built on top of standard application and service principal primitives, a scoping gap emerged that permitted administrators with this role to modify ownership of any service principal, create new credentials, and impersonate high‑privileged applications, exposing CI/CD pipelines, automation workflows, and the entire tenant to takeover .
Learning Objectives
- Understand how the Agent ID Administrator role’s scoping logic flaw enabled unauthorized service principal takeover and privilege escalation
- Learn step‑by‑step exploitation techniques, including ownership modification, credential injection, and token‑based impersonation
- Gain practical commands and detection scripts to audit your tenant, hunt for signs of abuse, and implement effective mitigations
You Should Know
- How the Scoping Gap Enabled Service Principal Hijacking
The Microsoft Entra Agent ID Platform provides AI agents with first‑class identities in Entra ID, introducing object types such as blueprints, agent identities, and agent users. To manage this new control plane, Microsoft introduced the Agent ID Administrator role, which on paper was strictly scoped to agent‑related objects only . However, both agent identities and standard service principals share the same core object fields in Azure AD—identifiers, display names, owners, and credential slots. Because the role‑check logic failed to properly separate those object types, the Agent ID Administrator role could manage more identities than intended, including non‑agent service principals .
Silverfort researchers discovered that actions like updating agent identity owners allowed administrators to modify the ownership of any service principal in the tenant. A user with only the Agent ID Administrator role could assign themselves as the owner of a completely unrelated, high‑privileged service principal. Once ownership was established, the attacker could generate new credentials (client secrets or certificates) and authenticate as that targeted application. If the compromised service principal held elevated directory roles or high‑impact Graph API permissions, this takeover primitive provided a direct path to full compromise of the environment .
Step‑by‑step guide explaining what this does and how to use it:
The exploitation flow is simple and does not require advanced hacking skills:
- Step 1: Assign Ownership. The attacker, already granted (or able to grant themselves) the Agent ID Administrator role, uses the Microsoft Graph API to add their account as an owner of any target service principal. Because the role‑check logic failed to separate agent from non‑agent objects, this operation succeeds even though the role was not intended to manage non‑agent identities.
- Step 2: Generate Credentials. With ownership granted, the attacker creates a new client secret or uploads a certificate for the hijacked service principal. This step effectively “backdoors” the application identity.
- Step 3: Authenticate as the Target. Using the newly created credentials, the attacker authenticates to Microsoft Entra ID and requests an access token on behalf of the service principal. The token is issued with all the permissions and directory roles originally assigned to that service principal .
Why it matters: Many CI/CD pipelines, automation systems, and security tools rely on service principals with powerful Graph API permissions (e.g., Application.ReadWrite.All, Directory.ReadWrite.All). By taking over a privileged service principal, an attacker can bypass user‑centric defenses like MFA and Conditional Access because app‑only authentication flows do not require interactive user authentication .
- Detecting Agent ID Administrator Abuse and Privileged Service Principals
To understand your exposure and hunt for signs of this vulnerability, you need to audit two things: who has the Agent ID Administrator role, and which service principals hold privileged directory roles that could be hijacked. Microsoft and researchers have released practical commands for both Azure CLI and PowerShell.
Step‑by‑step guide explaining what this does and how to use it:
A. Identify all privileged service principals (Linux / Azure CLI):
The following script queries the Microsoft Graph API to discover service principals with admin‑level directory roles. It uses `az rest` and `jq` to filter only privileged roles and display each service principal alongside its assigned role.
BASE="https://graph.microsoft.com"
roles="$(az rest -m GET --url "${BASE}/beta/roleManagement/directory/roleDefinitions?$filter=isPrivileged eq true&$select=id,displayName" -o json)"
u="${BASE}/beta/roleManagement/directory/roleAssignments?$expand=principal($select=id,displayName)&$top=999"
{
echo -e "SP_NAME\tSP_ID\tROLE"
echo -e "--\t\t-"
while :; do
j="$(az rest -m GET --url "$u" -o json 2>/dev/null)" || break
jq -r --argjson roles "$roles" '
($roles.value | map(select(.displayName|test("Reader";"i")|not) | {key:.id, value:.displayName}) | from_entries) as $r
| .value[] | select(.principal."@odata.type"=="microsoft.graph.servicePrincipal")
| select($r[.roleDefinitionId] != null)
| [.principal.displayName, (.principal.id // .principalId), $r[.roleDefinitionId]] | @tsv
' <<<"$j"
u="$(jq -r '."@odata.nextLink"//empty' <<<"$j")"
[[ -z "$u" ]] && break
done | sort -t$'\t' -k3,3
}
This script enumerates all role assignments, filters for service principals, and displays only those assigned to privileged directory roles (e.g., Global Administrator, Application Administrator). The output helps you identify which non‑human identities would be most valuable to an attacker .
B. Find all users and groups assigned the Agent ID Administrator role (PowerShell):
Using the Microsoft Entra PowerShell module (or the older AzureAD module), you can list every assignment of the vulnerable role.
Connect to Microsoft Entra ID
Connect-Entra -Scopes "RoleManagement.Read.All"
Get the role definition for Agent ID Administrator
$role = Get-EntraRoleDefinition | Where-Object { $_.DisplayName -eq "Agent ID Administrator" }
Get all role assignments
$assignments = Get-EntraRoleAssignment -Filter "roleDefinitionId eq '$($role.Id)'"
Display each principal (user or group) that holds the role
$assignments | ForEach-Object {
$principal = Get-EntraObjectById -Ids $_.PrincipalId
[bash]@{
PrincipalType = $principal."@odata.type"
DisplayName = $principal.DisplayName
PrincipalId = $principal.Id
}
}
Any user or group listed here could, before the April 2026 patch, hijack any service principal in the tenant. Even after the patch, these assignments represent a highly sensitive role that should be tightly controlled .
C. Hunt for suspicious owner changes and credential creations:
To detect exploitation attempts, monitor Entra ID audit logs for the following activities:
Connect to Microsoft Graph PowerShell SDK Connect-MgGraph -Scopes "AuditLog.Read.All" Find owner changes to service principals (look for unusual ActivityDateTime) Get-MgAuditLogDirectoryAudit -Filter "activityDisplayName eq 'Add owner to application'" | Select-Object ActivityDateTime, InitiatedBy, TargetResources, AdditionalDetails Find new credential creations Get-MgAuditLogDirectoryAudit -Filter "activityDisplayName eq 'Add service principal credentials'" | Select-Object ActivityDateTime, InitiatedBy, TargetResources
Unexpected owner additions or credential creations—especially when initiated by a user with the Agent ID Administrator role—are strong indicators of compromise .
3. Securing Your Tenant Against Role Scoping Flaws
Even though Microsoft has patched this specific flaw (the Agent ID Administrator role can no longer modify owners of non‑agent service principals as of April 9, 2026), the incident highlights a broader pattern: as new identity layers are introduced, permission boundaries must be carefully enforced . Your organization should take immediate steps to harden Entra ID configuration.
Step‑by‑step guide explaining what this does and how to use it:
- Enforce least privilege and use PIM: Regularly review all highly privileged role assignments (Global Administrator, Application Administrator, Privileged Role Administrator, and now Agent ID Administrator). Use Privileged Identity Management (PIM) to convert permanent assignments into just‑in‑time (JIT) elevation with approval workflows and time limits .
- Audit service principal ownership monthly: Service principal ownership is a legitimate administrative feature, but it becomes a liability when regular users own sensitive applications. Run the audit script from Section 2 monthly to detect any service principal with an owner who should not have that level of control. For any orphaned or over‑privileged service principal, remove unnecessary owners and rotate credentials.
Example: list all owners of a specific service principal (Azure CLI)
SP_OBJECT_ID="00000000-0000-0000-0000-000000000000"
az rest -m GET --url "https://graph.microsoft.com/v1.0/servicePrincipals/${SP_OBJECT_ID}/owners" --query "value[].{DisplayName:displayName, UserPrincipalName:userPrincipalName}"
- Require MFA and Conditional Access for all role assignments: Even app‑only service principals should be protected. Use Conditional Access policies to block authentication from untrusted locations or to require compliant devices before issuing tokens. For human users who manage role assignments, enforce phishing‑resistant MFA (e.g., FIDO2 keys or Certificate‑Based Authentication) .
- Monitor for unusual token requests: After hijacking a service principal, an attacker will request tokens using the stolen credentials. Integrate Entra ID sign‑in logs with your SIEM and create alerts for:
- Token requests from new IP addresses or locations
- Token requests for multiple distinct applications in a short time window
- Token requests that use app‑only authentication flow (
client_credentials) where only user‑based authentication was historically seen - Rotate all service principal credentials regularly: Implement a secret rotation policy. For service principals used in CI/CD, rotate client secrets every 30–60 days and store them in Azure Key Vault managed identities where possible. For certificate‑based authentication, set short validity periods and use automated renewal .
- Extending Defenses to Other Entra ID Privilege Escalation Vectors
The Agent ID Administrator flaw is not an isolated incident. Service principal ownership abuse is a well‑known attack vector in Entra ID. In a typical scenario, a compromised low‑privileged user who owns an enterprise application (service principal) that is assigned a privileged role can add a client secret to that service principal, authenticate as the application (bypassing MFA), and then use the app’s role to reset a Global Administrator’s password or issue a Temporary Access Pass (TAP), achieving full tenant compromise . Similarly, attackers can hijack first‑party applications like the Office 365 Exchange Online service principal, which inherently has powerful permissions such as Domain.ReadWrite.All, to add a malicious federated domain and forge SAML tokens as any synchronized user .
Step‑by‑step guide explaining what this does and how to use it:
Preventive hardening checklist:
- Lock application registrations that are highly sensitive. Use app instance property locks to prevent modifications to the app registration, including adding credentials or changing owners, even by Global Administrators. This is the strongest protection against service principal abuse .
- Remove over‑permissioned service principals. Any service principal that has been granted
Application.ReadWrite.All,Directory.ReadWrite.All, or `RoleManagement.ReadWrite.Directory` should be treated as equivalent to a Global Administrator. Reduce these permissions wherever possible and replace them with more granular Graph API scopes. - Implement continuous monitoring of application consent. Use Microsoft Defender for Cloud Apps or a third‑party tool to monitor and alert on OAuth consent grants, especially for applications that request high‑privilege permissions.
- Run automated privilege escalation detection. The following PowerShell script (part of the Entra ID Incident Response toolkit) detects users with multiple failed sign‑ins followed by a successful sign‑in—an indicator of password spray or credential stuffing attacks that often precede service principal abuse.
Detect multiple failed sign-ins followed by a successful sign-in
Requires the Microsoft Graph PowerShell SDK and appropriate permissions
Connect-MgGraph -Scopes "AuditLog.Read.All"
$failedSignIns = Get-MgAuditLogSignIn -Filter "status/errorCode ne 0" -Top 1000
$successfulSignIns = Get-MgAuditLogSignIn -Filter "status/errorCode eq 0" -Top 500
Group by user and look for patterns where failed attempts cluster before a success
$suspicious = $failedSignIns | Group-Object UserId | ForEach-Object {
$user = $<em>.Name
$failCount = $</em>.Count
$successAfter = $successfulSignIns | Where-Object { $<em>.UserId -eq $user -and $</em>.CreatedDateTime -gt ($_.Group[bash].CreatedDateTime) }
if ($failCount -ge 3 -and $successAfter) {
[bash]@{
User = $user
FailCount = $failCount
SuccessTime = $successAfter.CreatedDateTime
}
}
}
$suspicious
This script is adapted from the community CFIR (Cloud Forensic and Incident Response) toolkit and can be extended to send alerts to your SIEM .
5. Timeline, Patch Status, and What Remains Vulnerable
Understanding the disclosure timeline helps organizations verify their patch status and adjust risk assessments.
Step‑by‑step guide explaining what this does and how to use it:
- February 24, 2026 – Silverfort researchers identify the scope overreach vulnerability.
- March 1, 2026 – Report submitted to the Microsoft Security Response Center (MSRC).
- March 3, 2026 – MSRC opens a case and begins investigation.
- April 9, 2026 – Microsoft deploys a comprehensive fix across all cloud environments (worldwide). The update ensures the Agent ID Administrator role can no longer modify ownership of non‑agent service principals .
What remains vulnerable: Although Microsoft patched the scoping logic, any tenant that has not reviewed its role assignments may still have the Agent ID Administrator role granted to users or groups unnecessarily. Moreover, the fix does not automatically remove previously added owners or credentials. If an attacker added themselves as an owner or created a client secret before the patch was applied, those backdoors remain active until manually removed. Your immediate post‑patch actions should be:
1. Remove all unnecessary Agent ID Administrator assignments.
- Audit every service principal for unexpected owners (especially those added between February 24 and April 9, 2026).
- Rotate credentials for all privileged service principals, regardless of whether abuse is suspected .
What Undercode Say
- Key Takeaway 1: The Agent ID Administrator role flaw demonstrates that identity layers built on shared primitives must enforce strict type separation; otherwise, new roles can unintentionally become “shadow Global Admins.” Microsoft’s April 2026 patch blocks non‑agent ownership changes, but organizations must actively audit and clean up legacy assignments.
- Key Takeaway 2: Service principal abuse is a modern identity‑based attack path that bypasses MFA and Conditional Access. Defenses require a combination of JIT elevation (PIM), continuous monitoring of audit logs for owner/credential changes, and application‑level locks on critical service principals.
This incident underscores a broader challenge: as AI agents and non‑human identities proliferate, security boundaries must be retrofitted into existing directory schemas. Organizations that treat service principals as “just another account” will continue to be exposed. The most effective long‑term strategy is to adopt Zero Trust principles for non‑human entities—rotate credentials automatically, enforce least privilege, and never grant permanent high‑privilege role assignments without just‑in‑time approval workflows. The Agent ID Administrator flaw also highlights a recurring pattern in cloud identity platforms: preview features often ship with incomplete permission validation, and production tenants adopt them before security boundaries are fully tested. Security teams should now routinely audit every built‑in role in Entra ID, especially those in preview or newly added, using scripts similar to those provided above.
Prediction
This vulnerability will catalyze a wave of additional research into role scoping flaws across all major cloud identity providers (Azure Entra ID, AWS IAM, Google Cloud IAM). Expect at least three to five similar “scope overreach” disclosures within the next 12 months, particularly for roles that manage service accounts, bots, or AI agents. Attackers will increasingly shift from compromising human accounts to hijacking service principals, because app‑only authentication avoids MFA and leaves fewer traces in interactive sign‑in logs. Defenders will need to adopt continuous, automated identity threat detection and response (ITDR) solutions that correlate role assignments, ownership changes, and token issuance across the entire tenant—shifting from periodic manual audits to real‑time behavioral analytics for non‑human identities.
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