Detection rules › Sigma

Potential DLL File Download Via PowerShell Invoke-WebRequest

Severity
medium
Author
Florian Roth (Nextron Systems), Hieu Tran
Source
upstream

Detects potential DLL files being downloaded using the PowerShell Invoke-WebRequest or Invoke-RestMethod cmdlets.

MITRE ATT&CK coverage

TacticTechniques
ExecutionT1059.001 Command and Scripting Interpreter: PowerShell
Command & ControlT1105 Ingress Tool Transfer

Event coverage

ProviderEvent IDTitle
Sysmon1Process creation
Security-Auditing4688A new process has been created.

Stages and Predicates

Stage 1: selection

or:
CommandLine|contains: 'IRM '
CommandLine|contains: 'IWR '
CommandLine|contains: 'Invoke-RestMethod '
CommandLine|contains: 'Invoke-WebRequest '
CommandLine|contains: .dll
CommandLine|contains: OutFile
CommandLine|contains: http

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
CommandLinematch
  • .dll corpus 15 (sigma 15)
  • IRM
  • IWR corpus 2 (sigma 2)
  • Invoke-RestMethod corpus 2 (sigma 2)
  • Invoke-WebRequest corpus 4 (sigma 4)
  • OutFile
  • http corpus 31 (sigma 31)