Overview 💥
Partners and their customers may encounter errors when attempting to edit, disable, or delete an inspector from the Liongard platform. The disable/edit/delete operation fails with an error message similar to:
Error Message: "undefined" is not valid JSON or Failed to disable inspector
HTTP Status: 500 Internal Server Error (or 400 Bad Request)
Affected Action: Edit friendly name, disable inspector, or delete inspector
API Endpoint: /api/v1/launchpoints/{ID}/ returns validation failure
Trigger: Attempting any modification to inspector configuration
✅ Confirmed Safe:
The inspector itself is not compromised or malfunctioning in terms of security. The issue stems from corrupted credential metadata stored in the Liongard, not active scanning or agent behavior.
This affects all inspector types — Network Discovery, Windows Workstation, Active Directory, and others — when their credential fields contain malformed data.
Why This Happens? 🤔
🌟 Corrupted Secure Launchpoint Variables
Liongard inspectors that require credentials (such as SNMP community strings, database passwords, API keys, or authentication tokens) store this sensitive data in Secure Launchpoint Variables. These credentials are encrypted and stored in the backend database.
In rare cases, credential data can become corrupted or malformed, causing the serialized credential metadata to fail JSON parsing when the backend attempts to validate or modify the inspector configuration.
Common scenarios where this occurs:
Inspector has been in failed state since long time.
Partial or interrupted credential updates during inspector creation or reconfiguration.
Legacy credential data that failed to migrate during platform upgrades.
Corrupted encryption/decryption of sensitive fields.
Manual database edits or failed API operations that left invalid credential structures
When you attempt to edit, disable, or delete an inspector with corrupted credentials, the backend must load and validate the inspector’s entire configuration — including its secure variables. If the credential metadata is malformed, the JSON deserialization fails, blocking all modification operations.
🌟 Why Other Inspectors Work Normally?
Other inspectors (even of the same type on the same agent) work fine because their credential data is valid and properly serialized. Only the inspector with corrupted credentials is affected.
Liongard Inspector Behavior 🧑🏫
Understanding how inspector credentials are managed helps determine whether the issue is related to credential corruption.
✅ Liongard DOES | ❌ Liongard Does NOT |
Load and validate entire inspector configuration, including secure credentials | Delete credentials without prior validation |
Deserialize credential metadata to JSON to verify structure integrity | Allow modifications if credential data is corrupted |
Return 400/500 errors if credential parsing fails | Automatically repair malformed credential data |
Lock modification operations until credentials are repaired | Expose or log unencrypted credential values |
Allow credential fields to be cleared to purge corrupted data | Attempt to recover corrupted encrypted fields |
Steps to Resolve 👨🔧
The recommended resolution is to clear the corrupted credential fields and re-enter them manually. This purges the malformed metadata and allows normal operations to resume.
Step 1 — Navigate to the Inspector
Log in to the Liongard platform
Go to Admin → Inspectors
Locate the inspector that fails to disable/edit/delete
Click to edit the inspector configuration
Step 2 — Identify Secure Credential Fields
Secure credential fields vary by inspector type. Common examples include:
Inspector Type | Secure Fields |
Azure | Tenant ID,Client ID, Client Secrets |
Network Discovery | SNMP Read Community String,SNMP Username and Authentication and Encryption Passwords |
pfSense, WatchGuard, Cisco Small Business Solution (SBS) Switch Inspector | SSH Username, SSH Password_or_ SSH Private Key, SSH Passphrase for Private Key |
SonicWall v7/v6 | API/SSH Username & Password |
Scroll through the inspector configuration and identify any fields marked as UserName, passwords, port number or strings entered during inspector setup or shows ✅.
Step 3 — Clear Credential Fields
For each secure credential field:
Click into the field or edit option (Pencil icon✏️)
Delete the existing value completely
Leave the field empty
Now follow based on inspector behavior:
1️⃣ If fields are NOT mandatory:
Leave fields empty
Continue to Step 4
2️⃣ If fields are mandatory (Save fails or fields require input):
Re-enter valid credential values
Continue to Step 4
Step 4 — Save the Configuration
Click Save
Observe the result:
⏯️ If Save succeeds → credential corruption has been purged ✅
⏯️ If Save fails with the same JSON error → corruption may be in other fields; repeat Steps 2–4 for remaining secure fields
Step 5 — Verify Disable/Edit/Delete Works
Once the configuration saves:
Return to the inspector list
Attempt to:
Disable
Edit
Delete
Confirm the operation completes successfully
If all operations now work, the issue is resolved. The corrupted credential data has been cleared.
Why Clearing Credentials Works? 🧐
Clearing credential fields forces the platform to:
Remove corrupted encrypted metadata
Rebuild a clean credential structure on save
Bypass JSON parsing failures
Once reset, normal operations should resume.
When to Contact Liongard Support 🦁
If clearing credentials does not resolve the issue, the corruption may reside at a deeper level in the credential storage system.
Contact Liongard Support with:
Inspector name and ID (Launchpoint ID if available)
Error message shown during disable/edit/delete attempt
Inspector type (Network Discovery, Windows Workstation, etc.)
Steps already taken to resolve the issue
Liongard Support can:
Access backend database logs to identify the corrupted field
Manually try to repair or purge the corrupted credential record
Preventing Credential Corruption 🚀
Recommendation | Benefit |
Use strong, properly formatted credentials | Reduces serialization errors during storage |
Avoid copying credentials from unsupported sources | Prevents encoding/decoding issues |
Test inspector modifications in a non-production environment first | Catches configuration issues before affecting live inspectors |
Review inspector credentials during quarterly compliance audits | Identifies stale or corrupted credential data early |
Document credentials securely (in a vault, not in notes) | Enables quick re-entry if corruption occurs |
Update Liongard platform regularly | Ensures latest credential handling patches are deployed |
Troubleshooting Checklist ✅
Step | Action | Expected Result |
1 | Verify the inspector fails to disable/edit/delete | Error message appears with “undefined is not valid JSON” or 400/500 status |
2 | Edit the inspector and scroll to secure credential fields | Credential fields are visible and appear populated |
3 | Clear all secure credential fields | Fields are now empty |
4 | Click Save | Configuration saves successfully (no error) |
5 | Return to inspector list and attempt disable | Disable operation completes ✅ |
6 | If issue persists | Contact Liongard Support with inspector ID and error details |