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Detection rules › Sigma

Security Software Discovery Via Powershell Script

Severity
medium
Author
frack113, Anish Bogati, Nasreddine Bencherchali (Nextron Systems)
Source
upstream

Detects calls to "get-process" where the output is piped to a "where-object" filter to search for security solution processes. Adversaries may attempt to get a listing of security software, configurations, defensive tools, and sensors that are installed on a system or in a cloud environment. This may include things such as firewall rules and anti-virus

MITRE ATT&CK coverage

TacticTechniques
DiscoveryT1518.001 Software Discovery: Security Software Discovery

Event coverage

ProviderEvent IDTitle
PowerShell4104Creating Scriptblock text (MessageNumber of MessageTotal).

Stages and Predicates

Stage 1: all of selection_cmdlet

or:
ScriptBlockText|contains: 'get-process | \?'
ScriptBlockText|contains: 'get-process | where'
ScriptBlockText|contains: 'gps | \?'
ScriptBlockText|contains: 'gps | where'

Stage 2: all of selection_field

or:
ScriptBlockText|contains: 'Company -like'
ScriptBlockText|contains: 'Description -like'
ScriptBlockText|contains: 'Name -like'
ScriptBlockText|contains: 'Path -like'
ScriptBlockText|contains: 'Product -like'

Stage 3: all of selection_keywords

or:
ScriptBlockText|contains: '\*avira\*'
ScriptBlockText|contains: '\*carbonblack\*'
ScriptBlockText|contains: '\*cylance\*'
ScriptBlockText|contains: '\*defender\*'
ScriptBlockText|contains: '\*kaspersky\*'
ScriptBlockText|contains: '\*malware\*'
ScriptBlockText|contains: '\*sentinel\*'
ScriptBlockText|contains: '\*symantec\*'
ScriptBlockText|contains: '\*virus\*'

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
ScriptBlockTextmatch
  • Company -like
  • Description -like
  • Name -like
  • Path -like
  • Product -like
  • \*avira\*
  • \*carbonblack\*
  • \*cylance\*
  • \*defender\*
  • \*kaspersky\*
  • \*malware\*
  • \*sentinel\*
  • \*symantec\*
  • \*virus\*
  • get-process | \?
  • get-process | where
  • gps | \?
  • gps | where

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.