> 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 | Persistence (TA0003), Defense Evasion (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 | Persistence (TA0003), Defense Evasion (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.
---
# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.
## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.
Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:
```
GET https://cortex-docs.paloaltonetworks.com/analytics-alerts/alerts-by-name/modification-of-the-ad-fs-identityserver-configuration-file.md?ask=&goal=
```
`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.
Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.