Startup/Logon Script added to Group Policy Object

## Triage and analysis

### Investigating Scheduled Task Execution at Scale via GPO

Group Policy Objects can be used by attackers as a mechanism for an attacker to instruct an arbitrarily large group of clients to
execute specified commands at Startup, Logon, Shutdown, and Logoff. This is done by creating/modifying the `scripts.ini` or
`psscripts.ini` files. The scripts are stored in the following path: `<GPOPath>\Machine\Scripts\`, `<GPOPath>\User\Scripts\`

#### Possible investigation steps:
- This attack abuses a legitimate mechanism of the Active Directory, so it is important to determine whether the activity is legitimate
and the administrator is authorized to perform this operation.
- Retrieve the contents of the script file, check for any potentially malicious commands and binaries.
- If the action is suspicious for the user, check for any other activities done by the user in the last 48 hours.

### False Positive Analysis
- Verify if the execution is allowed and done under change management, and legitimate.

### Related Rules
- Group Policy Abuse for Privilege Addition - b9554892-5e0e-424b-83a0-5aef95aa43bf
- Scheduled Task Execution at Scale via GPO - 15a8ba77-1c13-4274-88fe-6bd14133861e

### Response and Remediation
- Immediate response should be taken to validate activity, investigate and potentially isolate activity to prevent further
post-compromise behavior.

## Config

The 'Audit Detailed File Share' audit policy is required be configured (Success Failure).
Steps to implement the logging policy with with Advanced Audit Configuration:
```
Computer Configuration >
Policies >
Windows Settings >
Security Settings >
Advanced Audit Policies Configuration >
Audit Policies >
Object Access >
Audit Detailed File Share (Success,Failure)
```

The 'Audit Directory Service Changes' audit policy is required be configured (Success Failure).
Steps to implement the logging policy with with Advanced Audit Configuration:
```
Computer Configuration >
Policies >
Windows Settings >
Security Settings >
Advanced Audit Policies Configuration >
Audit Policies >
DS Access >
Audit Directory Service Changes (Success,Failure)
```