Detection rules › Sigma

Email Exifiltration Via Powershell

Severity
high
Author
Nasreddine Bencherchali (Nextron Systems), Azure-Sentinel (idea)
Source
upstream

Detects email exfiltration via powershell cmdlets

Event coverage

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

Stages and Predicates

Stage 1: selection

or:
Image|endswith: '\powershell.exe'
Image|endswith: '\pwsh.exe'
CommandLine|contains: -ExpandProperty
CommandLine|contains: -hidetableheaders
CommandLine|contains: Add-PSSnapin
CommandLine|contains: EmailAddresses
CommandLine|contains: Get-Recipient
CommandLine|contains: SmtpAddress

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
  • -ExpandProperty
  • -hidetableheaders
  • Add-PSSnapin corpus 2 (sigma 2)
  • EmailAddresses
  • Get-Recipient
  • SmtpAddress
Imageends_with
  • \powershell.exe corpus 143 (sigma 143)
  • \pwsh.exe corpus 140 (sigma 140)