Windows PowerShell Disabled Kerberos Pre-Authentication Discovery With PowerView
Description
The following analytic utilizes PowerShell Script Block Logging (EventCode=4104) to identify the execution of the Get-DomainUser
commandlet with specific parameters. Get-DomainUser
is part of PowerView, a PowerShell tool used to perform enumeration on Windows Active Directory networks. As the name suggests, Get-DomainUser
is used to identify domain users and combining it with -PreauthNotRequired
allows adversaries to discover domain accounts with Kerberos Pre Authentication disabled.\ Red Teams and adversaries alike use may leverage PowerView to enumerate these accounts and attempt to crack their passwords offline.
- Type: TTP
-
Product: Splunk Behavioral Analytics
- Last Updated: 2022-11-14
- Author: Michael Haag, Splunk
- ID: dc3f2af7-ca69-47ce-a122-9f9787e19417
Annotations
ATT&CK
Kill Chain Phase
- Exploitation
NIST
- DE.CM
CIS20
- CIS 10
CVE
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| from read_ba_enriched_events()
| eval timestamp = ucast(map_get(input_event,"time"),"long", null)
| eval metadata = ucast(map_get(input_event, "metadata"),"map<string, any>", null)
| eval metadata_uid = ucast(map_get(metadata, "uid"),"string", null)
| eval device=ucast(map_get(input_event,"device"), "map<string, any>", null)
| eval device_hostname=ucast(map_get(device,"hostname"), "string", null)
| eval process=ucast(map_get(input_event,"process"), "map<string, any>", null)
| eval process_file=ucast(map_get(process,"file"), "map<string, any>", null)
| eval process_file_path=ucast(map_get(process_file,"path"), "string", null)
| eval process_uid=ucast(map_get(process,"uid"), "string", null)
| eval process_cmd_line=ucast(map_get(process,"cmd_line"), "string", null)
| eval actor=ucast(map_get(input_event,"actor"), "map<string, any>", null)
| eval actor_user=ucast(map_get(actor,"user"), "map<string, any>", null)
| eval actor_user_uid=ucast(map_get(actor_user,"uid"), "string", null)
| where match_regex(process_cmd_line, /(?i)preauthnotrequired/)=true AND match_regex(process_cmd_line, /(?i)get-domainuser/)=true --finding_report--
Macros
The SPL above uses the following Macros:
windows_powershell_disabled_kerberos_pre-authentication_discovery_with_powerview_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.
- device.hostname
- process.file.path
- process.uid
- process.cmd_line
- actor.user.uid
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 PowerView for troubleshooting
Associated Analytic Story
RBA
Risk Score | Impact | Confidence | Message |
---|---|---|---|
54.0 | 60 | 90 | Disabled Kerberos Pre-Authentication Discovery With PowerView from $dest_device_id$ |
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/T1558/004/
- https://m0chan.github.io/2019/07/31/How-To-Attack-Kerberos-101.html
- https://stealthbits.com/blog/cracking-active-directory-passwords-with-as-rep-roasting/
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: 1