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Detection rules › Sigma

Renamed Whoami Execution

Status
test
Severity
critical
Log source
category process_creation, product windows
Author
Florian Roth (Nextron Systems)
Source
github.com/SigmaHQ/sigma

Detects the execution of whoami that has been renamed to a different name to avoid detection

MITRE ATT&CK coverage

TacticTechniques
Discovery

Telemetry coverage

ProviderRecord / event type
SysmonEvent ID 1: Process creation

Rule body

title: Renamed Whoami Execution
id: f1086bf7-a0c4-4a37-9102-01e573caf4a0
status: test
description: Detects the execution of whoami that has been renamed to a different name to avoid detection
references:
    - https://brica.de/alerts/alert/public/1247926/agent-tesla-keylogger-delivered-inside-a-power-iso-daa-archive/
    - https://app.any.run/tasks/7eaba74e-c1ea-400f-9c17-5e30eee89906/
author: Florian Roth (Nextron Systems)
date: 2021-08-12
modified: 2022-10-09
tags:
    - attack.discovery
    - attack.t1033
    - car.2016-03-001
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        OriginalFileName: 'whoami.exe'
    filter:
        Image|endswith: '\whoami.exe'
    condition: selection and not filter
falsepositives:
    - Unknown
level: critical

Stages and Predicates

Stage 0: condition

selection and not filter

Stage 1: selection

selection:
    OriginalFileName: 'whoami.exe'

Stage 2: not filter

filter:
    Image|endswith: '\whoami.exe'

Exclusions

The rule actively suppresses these predicates.

FieldKindExcluded valuesSearch
Imageends_with\whoami.exeexcludes:Image field:"Image" value:"\whoami.exe"

Indicators

These rows show field, operator, and value matches.

FieldKindValuesSearch
OriginalFileNameeq
  • whoami.exe corpus 9 (sigma 9)
field:"OriginalFileName" kind:eq value:"whoami.exe"