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Detection rules › Splunk

Detect Copy of ShadowCopy with Script Block Logging

Author
Michael Haag, Splunk
Source
upstream

The following analytic detects the use of PowerShell commands to copy the SAM, SYSTEM, or SECURITY hives, which are critical for credential theft. It leverages PowerShell Script Block Logging (EventCode=4104) to capture and analyze the full command executed. This activity is significant as it indicates an attempt to exfiltrate sensitive registry hives for offline password cracking. If confirmed malicious, this could lead to unauthorized access to credentials, enabling further compromise of the system and potential lateral movement within the network.

MITRE ATT&CK coverage

TacticTechniques
Credential AccessT1003.002 OS Credential Dumping: Security Account Manager

Event coverage

ProviderEvent IDTitle
PowerShell4104Creating Scriptblock text (MessageNumber of MessageTotal).

Stages and Predicates

Stage 1: search

search EventCode=4104 ScriptBlockText IN ("*System32\\config\\SAM*", "*System32\\config\\SECURITY*", "*System32\\config\\SYSTEM*") ScriptBlockText IN ("*[System.IO.File]::Copy*", "*copy*")

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)
ScriptBlockTextin
  • "*System32\\config\\SAM*"
  • "*System32\\config\\SECURITY*"
  • "*System32\\config\\SYSTEM*"
  • "*[System.IO.File]::Copy*"
  • "*copy*"

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.