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Detection rules › Sigma

Execution via stordiag.exe

Status
test
Severity
high
Log source
product windows, category process_creation
Author
Austin Songer (@austinsonger)
Source
github.com/SigmaHQ/sigma

Detects the use of stordiag.exe to execute schtasks.exe systeminfo.exe and fltmc.exe

MITRE ATT&CK coverage

TacticTechniques
StealthT1218 System Binary Proxy Execution

Event coverage

ProviderEventTitle
SysmonEvent ID 1Process creation
Security-AuditingEvent ID 4688A new process has been created.

Rule body yaml

title: Execution via stordiag.exe
id: 961e0abb-1b1e-4c84-a453-aafe56ad0d34
status: test
description: Detects the use of stordiag.exe to execute schtasks.exe systeminfo.exe and fltmc.exe
references:
    - https://strontic.github.io/xcyclopedia/library/stordiag.exe-1F08FC87C373673944F6A7E8B18CD845.html
    - https://twitter.com/eral4m/status/1451112385041911809
author: Austin Songer (@austinsonger)
date: 2021-10-21
modified: 2022-12-25
tags:
    - attack.stealth
    - attack.t1218
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        ParentImage|endswith: '\stordiag.exe'
        Image|endswith:
            - '\schtasks.exe'
            - '\systeminfo.exe'
            - '\fltmc.exe'
    filter:
        ParentImage|startswith: # as first is "Copy c:\windows\system32\stordiag.exe to a folder"
            - 'c:\windows\system32\'
            - 'c:\windows\syswow64\'
    condition: selection and not filter
falsepositives:
    - Legitimate usage of stordiag.exe.
level: high

Stages and Predicates

Stage 0: condition

selection and not filter

Stage 1: selection

selection:
    ParentImage|endswith: '\stordiag.exe'
    Image|endswith:
        - '\schtasks.exe'
        - '\systeminfo.exe'
        - '\fltmc.exe'

Stage 2: not filter

filter:
    ParentImage|startswith:
        - 'c:\windows\system32\'
        - 'c:\windows\syswow64\'

Exclusions

Top-level NOT(...) conjuncts: predicates this rule actively suppresses.

FieldKindExcluded values
ParentImagestarts_withc:\windows\system32\
ParentImagestarts_withc:\windows\syswow64\

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
  • \fltmc.exe corpus 3 (sigma 3)
  • \schtasks.exe corpus 56 (sigma 56)
  • \systeminfo.exe corpus 11 (sigma 11)
ParentImageends_with
  • \stordiag.exe