Windows PowerShell IIS Components WebGlobalModule Usage
Description
The following analytic detects the usage of PowerShell Cmdlets - New-WebGlobalModule, Enable-WebGlobalModule, and Set-WebGlobalModule, which are used to create, enable, or modify IIS Modules. This detection leverages PowerShell Script Block Logging, specifically monitoring EventCode 4104 for these cmdlets. This activity is significant as adversaries may use these lesser-known cmdlets to manipulate IIS configurations, similar to AppCmd.exe, potentially bypassing traditional defenses. If confirmed malicious, this could allow attackers to persist in the environment, manipulate web server behavior, or escalate privileges.
- Type: Anomaly
- Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Datamodel: Web
- Last Updated: 2024-05-14
- Author: Michael Haag, Splunk
- ID: 33fc9f6f-0ce7-4696-924e-a69ec61a3d57
Annotations
ATT&CK
Kill Chain Phase
- Installation
NIST
- DE.AE
CIS20
- CIS 10
CVE
Search
1
2
3
4
5
`powershell` EventCode=4104 ScriptBlockText IN("*New-WebGlobalModule*","*Enable-WebGlobalModule*","*Set-WebGlobalModule*")
| stats count min(_time) as firstTime max(_time) as lastTime by EventCode ScriptBlockText Computer user_id
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `windows_powershell_iis_components_webglobalmodule_usage_filter`
Macros
The SPL above uses the following Macros:
windows_powershell_iis_components_webglobalmodule_usage_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
Required fields
List of fields required to use this analytic.
- _time
- ScriptBlockText
- Computer
- EventCode
How To Implement
To successfully implement this analytic, you will need to enable PowerShell Script Block Logging on some or all endpoints. Additional setup here https://docs.splunk.com/Documentation/UBA/5.0.4.1/GetDataIn/AddPowerShell#Configure_module_logging_for_PowerShell.
Known False Positives
It is possible administrators or scripts may run these commands, filtering may be required.
Associated Analytic Story
RBA
Risk Score | Impact | Confidence | Message |
---|---|---|---|
64.0 | 80 | 80 | A PowerShell Cmdlet related to enabling, creating or modifying a IIS module has occurred on $Computer$. |
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.
Reference
- https://learn.microsoft.com/en-us/powershell/module/webadministration/new-webglobalmodule?view=windowsserver2022-ps
- https://www.microsoft.com/en-us/security/blog/2022/12/12/iis-modules-the-evolution-of-web-shells-and-how-to-detect-them/
- https://www.crowdstrike.com/wp-content/uploads/2022/05/crowdstrike-iceapple-a-novel-internet-information-services-post-exploitation-framework-1.pdf
- https://unit42.paloaltonetworks.com/unit42-oilrig-uses-rgdoor-iis-backdoor-targets-middle-east/
- https://www.secureworks.com/research/bronze-union
- https://github.com/redcanaryco/atomic-red-team/tree/master/atomics/T1505.004
Test Dataset
Replay any dataset to Splunk Enterprise by using our replay.py
tool or the UI.
Alternatively you can replay a dataset into a Splunk Attack Range
source | version: 2