Remote System Discovery with Adsisearcher

Try in Splunk Security Cloud

Description

The following analytic utilizes PowerShell Script Block Logging (EventCode=4104) to identify the [Adsisearcher] type accelerator being used to query Active Directory for domain computers. Red Teams and adversaries may leverage [Adsisearcher] to enumerate domain computers for situational awareness and Active Directory Discovery.

• Type: TTP

• Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud

• Last Updated: 2022-06-29
• Author: Mauricio Velazco, Splunk
• ID: 70803451-0047-4e12-9d63-77fa7eb8649c

Annotations

ATT&CK

ATT&CK

ID	Technique	Tactic
T1018	Remote System Discovery	Discovery

Kill Chain Phase

• Exploitation

NIST

• DE.CM

CIS20

• CIS 10

CVE

Search

`powershell` EventCode=4104 ScriptBlockText = "*adsisearcher*" AND ScriptBlockText = "*objectcategory=computer*" AND ScriptBlockText IN ("*findAll()*","*findOne()*") 
| stats count min(_time) as firstTime max(_time) as lastTime by EventCode ScriptBlockText Computer UserID 
| `security_content_ctime(firstTime)` 
| `remote_system_discovery_with_adsisearcher_filter`

Macros

The SPL above uses the following Macros:

• powershell
• security_content_ctime

remote_system_discovery_with_adsisearcher_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
• EventCode
• ScriptBlockText
• Computer
• UserID

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

Administrators or power users may use Adsisearcher for troubleshooting.

Associated Analytic Story

• Active Directory Discovery

RBA

Risk Score	Impact	Confidence	Message
15.0	30	50	Remote system discovery enumeration on $Computer$ by $user$

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://attack.mitre.org/techniques/T1018/
• https://devblogs.microsoft.com/scripting/use-the-powershell-adsisearcher-type-accelerator-to-search-active-directory/

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