CSRF protection in ServiceNow is designed for browser traffic—not integrations. When an external tool like AWS Glue receives “Invalid CSRF token” or “Your session has expired”, it often indicates a deeper issue involving authentication flow, OAuth configuration, or an unexpected redirect.
The tricky part?
The integration may work in other ServiceNow instances, but fail in one specific environment, confusing both teams.
This article explains why this happens and how to diagnose and fix it quickly.
What Causes CSRF Token Errors in Integrations?
A ServiceNow CSRF error typically appears only in two situations:
1. The incoming request is treated like a browser session
If ServiceNow mistakenly thinks the external system is acting like a browser (UI request), it enforces CSRF token validation.
2. The authentication flow redirects incorrectly
If OAuth fails and redirects to a login page, the external system receives HTML instead of JSON, and ServiceNow displays “session expired."
Integrations should never see a CSRF token error under normal OAuth conditions.
Why AWS Glue Might Trigger a CSRF Error
AWS Glue generally integrates with ServiceNow by performing:
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OAuth authentication
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REST API requests
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Data reads/writes
If Glue sees:
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“Invalid CSRF token”
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“Your session has expired. Click here to login again”
…it means ServiceNow did not accept the incoming credentials as API traffic.
Below are the real reasons this happens.
1. Incorrect OAuth Grant Type
This is the #1 cause.
Most integrations use:
✔ Client Credentials (client_id + client_secret)
But some teams accidentally configure:
❌ Resource Owner Password Credentials (ROPC)
This requires a username + password — not suitable for Glue.
If Glue sends only client ID + secret, and your instance expects the other grant type, ServiceNow redirects to the login page → triggering the CSRF/session expired error.
2. OAuth Client ID Mismatch
Each ServiceNow instance typically has a different client ID for the same application registry.
If AWS Glue is configured with:
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correct client ID for DEV
-
correct client ID for PROD
-
❌ but wrong or old client ID for TEST
…the authentication silently fails and ServiceNow falls back to the login URL.
This results in a misleading CSRF message.
3. The “External Logout Redirect” URL Is Misleading
Identity Provider configuration sometimes contains:
When OAuth authentication fails, the system mistakenly redirects to this URL.
Glue receives:
HTML page saying “Your session has expired”
→ treated internally as a CSRF failure.
This confuses both sides because the message looks unrelated.
4. The Integration User Account Is Locked
If the integration uses Resource Owner flow (even unintentionally):
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the actual ServiceNow user behind it must not be locked
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If the “xyz” user that set up Glue is locked → authentication fails → login redirect happens → CSRF-tinted error
This explains scenarios like:
✔ Works in other instances
❌ Fails in one where xyz is locked
5. Instance-Specific Redirect or SSO Policy
Sometimes, one instance may have:
-
a stricter SSO policy
-
more restrictive login rules
-
IP filtering that triggers a redirect
These subtle differences can cause OAuth to misbehave in only one environment.
6. ServiceNow Treating the API Endpoint as UI
If the wrong endpoint is used (for example, a UI page instead of /api), ServiceNow expects CSRF tokens and blocks the call.
Even a missing /now prefix can cause this.
7. Auth Scope Confusion
If the OAuth app registry defines scopes like:
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user_account -
table.read -
global
…but Glue is configured to request a scope that is not registered in that environment, OAuth rejects the request and redirects to login.
Thus → “session expired.”
How to Diagnose the Issue
Here is a clean, systematic approach.
Step 1 — Check the OAuth transaction logs
Go to:
sys_oauth_credential → “OAuth Transaction Logs”
Failed transactions clearly show:
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wrong grant type
-
invalid client ID
-
unexpected redirect
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authentication errors
Step 2 — Impersonate the Integration User
If ROPC is used:
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impersonate the user configured in Glue
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check whether it is locked
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check whether it is active
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check if password expired
Step 3 — Compare OAuth App Registry Across Instances
Check these fields:
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OAuth name
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Client ID
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Client Secret
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Token URL
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Redirect URL
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Grant Types
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Scopes
When the integration works in one instance and not another, at least one of these fields differs.
Step 4 — Ask Glue Team for Their Logs
Glue logs will show:
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whether token URL returned HTML
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the redirect URL
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the HTTP error code
If they provide a login page instead of JSON → OAuth is broken.
Step 5 — Ensure Glue Is Calling /token and /api Endpoints
The valid pattern is usually:
and APIs under:
Anything else → browser rules applied → CSRF triggered.
Final Thoughts
CSRF token errors in integrations can be misleading, but the root cause is almost always related to OAuth flow issues—not actual CSRF protection.
By checking:
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grant type
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OAuth client ID
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scopes
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redirect behavior
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integration user status
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endpoint URLs
You can resolve the issue in minutes and bring the integration back online.
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