> For the complete documentation index, see [llms.txt](https://cortex-docs.paloaltonetworks.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://cortex-docs.paloaltonetworks.com/analytics-alerts/alerts-by-name/modification-of-the-ad-fs-identityserver-configuration-file.md).
# Modification of the AD FS IdentityServer configuration file
### Synopsis
| Field | Value |
| -------------------- | ---------------------------------------------- |
| Activation Period | 14 Days |
| Training Period | 30 Days |
| Test Period | N/A (single event) |
| Deduplication Period | 1 Day |
| Required Data | XDR Agent with eXtended Threat Hunting (XTH) |
| Detection Modules | Identity Analytics |
| Detector Tags | Active Directory Federation Services Analytics |
| ATT\&CK Tactic | Stealth (TA0005) |
| ATT\&CK Technique | Hijack Execution Flow (T1574) |
| Severity | Informational |
### Description
The AD FS service configuration file was modified.
### Attacker's Goals
The attacker's goal is to establish a persistent, high-privilege backdoor by forcing the service to load a malicious configuration that enables remote code execution and the bypass of security controls like MFA.
### Investigative actions
* Check if the AD FS service was stopped or restarted around the time of modification.
* Investigate the process and user that performed the write operation for signs of compromise.
### Variations
Suspicious Modification of the AD FS IdentityServer configuration file
**Synopsis**
| Field | Value |
| ----------------- | ----------------------------- |
| ATT\&CK Tactic | Stealth (TA0005) |
| ATT\&CK Technique | Hijack Execution Flow (T1574) |
| Severity | Low |
**Description**
The AD FS service configuration file was modified.
**Attacker's Goals**
The attacker's goal is to establish a persistent, high-privilege backdoor by forcing the service to load a malicious configuration that enables remote code execution and the bypass of security controls like MFA.
**Investigative actions**
* Check if the AD FS service was stopped or restarted around the time of modification.
* Investigate the process and user that performed the write operation for signs of compromise.
---
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