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Windows Domain Account Discovery Via Get-NetComputer

Author
Teoderick Contreras, Splunk
Source
upstream

The following analytic detects the execution of the PowerView PowerShell cmdlet Get-NetComputer, which is used to query Active Directory for user account details such as "samaccountname," "accountexpires," "lastlogon," and more. It leverages Event ID 4104 from PowerShell Script Block Logging to identify this activity. This behavior is significant as it may indicate an attempt to gather user account information, which is often a precursor to further malicious actions. If confirmed malicious, this activity could lead to unauthorized access, privilege escalation, or lateral movement within the network.

MITRE ATT&CK coverage

TacticTechniques
DiscoveryT1087.002 Account Discovery: Domain Account

Event coverage

ProviderEvent IDTitle
PowerShell4104Creating Scriptblock text (MessageNumber of MessageTotal).

Stages and Predicates

Stage 1: search

search EventCode=4104 ScriptBlockText="*Get-NetComputer*" ScriptBlockText IN ("*accountexpires*", "*lastlogoff*", "*lastlogon*", "*logoncount*", "*pwdlastset*", "*samaccountname*")

Stage 2: fillnull

fillnull

Stage 3: stats

stats BY dest, signature, signature_id, user_id, vendor_product, EventID, Guid, Opcode, Name, Path, ProcessID, ScriptBlockId, ScriptBlockText

Stage 4: search

search

Stage 5: search

search

Stage 6: search

search `macro`

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
EventCodeeq
  • 4104 corpus 108 (splunk 108)
ScriptBlockTexteq
  • "*Get-NetComputer*" corpus 3 (splunk 3)
ScriptBlockTextin
  • "*accountexpires*"
  • "*lastlogoff*"
  • "*lastlogon*"
  • "*logoncount*"
  • "*pwdlastset*" corpus 2 (splunk 2)
  • "*samaccountname*" corpus 2 (splunk 2)

Neighbors

Broader alternatives (more inclusive than this rule)

These rules match a superset of what this rule catches. They cover the same events plus more. Use them if you want wider coverage and can absorb more false positives.