Detection rules › Sigma

Whoami.EXE Execution From Privileged Process

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

Detects the execution of "whoami.exe" by privileged accounts that are often abused by threat actors

MITRE ATT&CK coverage

TacticTechniques
DiscoveryT1033 System Owner/User Discovery

Event coverage

ProviderEventTitle
SysmonEvent ID 1Process creation

Rule body yaml

title: Whoami.EXE Execution From Privileged Process
id: 79ce34ca-af29-4d0e-b832-fc1b377020db
related:
    - id: 80167ada-7a12-41ed-b8e9-aa47195c66a1
      type: obsolete
status: test
description: Detects the execution of "whoami.exe" by privileged accounts that are often abused by threat actors
references:
    - https://speakerdeck.com/heirhabarov/hunting-for-privilege-escalation-in-windows-environment
    - https://web.archive.org/web/20221019044836/https://nsudo.m2team.org/en-us/
author: Florian Roth (Nextron Systems), Teymur Kheirkhabarov
date: 2022-01-28
modified: 2023-12-04
tags:
    - attack.privilege-escalation
    - attack.discovery
    - attack.t1033
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        - OriginalFileName: 'whoami.exe'
        - Image|endswith: '\whoami.exe'
    selection_user:
        User|contains:
            - 'AUTHORI'
            - 'AUTORI'
            - 'TrustedInstaller'
    condition: all of selection_*
falsepositives:
    - Unknown
level: high

Stages and Predicates

Stage 0: condition

all of selection_*

Stage 1: selection_img

selection_img:
    - OriginalFileName: 'whoami.exe'
    - Image|endswith: '\whoami.exe'

Stage 2: selection_user

selection_user:
    User|contains:
        - 'AUTHORI'
        - 'AUTORI'
        - 'TrustedInstaller'

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
Imageends_with
  • \whoami.exe corpus 19 (sigma 19)
OriginalFileNameeq
  • whoami.exe corpus 9 (sigma 9)
Usermatch
  • AUTHORI corpus 14 (sigma 14)
  • AUTORI corpus 14 (sigma 14)
  • TrustedInstaller