WhoAmI as Parameter

Hunt Hypothesis

Detects a suspicious process command line that uses whoami as first parameter (as e.g. used by EfsPotato)

Detection Rule

Sigma (Original)

title: WhoAmI as Parameter
id: e9142d84-fbe0-401d-ac50-3e519fb00c89
status: test
description: Detects a suspicious process command line that uses whoami as first parameter (as e.g. used by EfsPotato)
references:
    - https://twitter.com/blackarrowsec/status/1463805700602224645?s=12
author: Florian Roth (Nextron Systems)
date: 2021-11-29
modified: 2022-12-25
tags:
    - attack.discovery
    - attack.t1033
    - car.2016-03-001
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        CommandLine|contains: '.exe whoami'
    condition: selection
falsepositives:
    - Unknown
level: high

KQL (Azure Sentinel)

imProcessCreate
| where TargetProcessCommandLine contains ".exe whoami"

Required Data Sources

False Positive Guidance

• Unknown

MITRE ATT&CK Context

• Tactic: Discovery
• Technique: T1033 — T1033

References

• https://twitter.com/blackarrowsec/status/1463805700602224645?s=12
• SigmaHQ Rule