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GetAdComputer with PowerShell Script Block

Author
Mauricio Velazco, Splunk
Source
upstream

The following analytic detects the execution of the Get-AdComputer PowerShell commandlet using PowerShell Script Block Logging (EventCode=4104). This detection leverages script block text to identify when this commandlet is run. The Get-AdComputer commandlet is significant as it can be used by adversaries to enumerate all domain computers, aiding in situational awareness and Active Directory discovery. If confirmed malicious, this activity could allow attackers to map the network, identify targets, and plan further attacks, potentially leading to unauthorized access and data exfiltration.

MITRE ATT&CK coverage

TacticTechniques
DiscoveryT1018 Remote System Discovery

Event coverage

ProviderEvent IDTitle
PowerShell4104Creating Scriptblock text (MessageNumber of MessageTotal).

Stages and Predicates

Stage 1: search

search EventCode=4104 ScriptBlockText="*Get-AdComputer*"

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 `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-AdComputer*"

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.