Detection rules › Sigma

Use NTFS Short Name in Image

Severity
medium
Author
frack113, Nasreddine Bencherchali (Nextron Systems)
Source
upstream

Detect use of the Windows 8.3 short name. Which could be used as a method to avoid Image based detection

MITRE ATT&CK coverage

TacticTechniques
Defense EvasionT1564.004 Hide Artifacts: NTFS File Attributes

Event coverage

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

Stages and Predicates

Stage 1: selection

or:
Image|contains: '~1.bat'
Image|contains: '~1.dll'
Image|contains: '~1.exe'
Image|contains: '~1.hta'
Image|contains: '~1.js'
Image|contains: '~1.msi'
Image|contains: '~1.ps1'
Image|contains: '~1.tmp'
Image|contains: '~1.vbe'
Image|contains: '~1.vbs'
Image|contains: '~2.bat'
Image|contains: '~2.dll'
Image|contains: '~2.exe'
Image|contains: '~2.hta'
Image|contains: '~2.js'
Image|contains: '~2.msi'
Image|contains: '~2.ps1'
Image|contains: '~2.tmp'
Image|contains: '~2.vbe'
Image|contains: '~2.vbs'

Stage 2: not 1 of filter_main_generic_parent

ParentImage: 'C:\Windows\explorer.exe'

Stage 3: not 1 of filter_optional_*

or:
Image|endswith: '\VCREDI~1.EXE'
Image: 'C:\PROGRA~1\WinZip\WZPREL~1.EXE'
ParentImage|endswith: '\WebEx\WebexHost.exe'
ParentImage|endswith: '\thor\thor64.exe'

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
  • \VCREDI~1.EXE
Imageeq
  • C:\PROGRA~1\WinZip\WZPREL~1.EXE
Imagematch
  • ~1.bat
  • ~1.dll
  • ~1.exe
  • ~1.hta
  • ~1.js
  • ~1.msi
  • ~1.ps1
  • ~1.tmp
  • ~1.vbe
  • ~1.vbs
  • ~2.bat
  • ~2.dll
  • ~2.exe
  • ~2.hta
  • ~2.js
  • ~2.msi
  • ~2.ps1
  • ~2.tmp
  • ~2.vbe
  • ~2.vbs
ParentImageends_with
  • \WebEx\WebexHost.exe corpus 3 (sigma 3)
  • \thor\thor64.exe corpus 3 (sigma 3)
ParentImageeq
  • C:\Windows\explorer.exe corpus 2 (sigma 2)