Detection rules › Sigma

Potential Persistence Via Notepad++ Plugins

Severity
medium
Author
Nasreddine Bencherchali (Nextron Systems)
Source
upstream

Detects creation of new ".dll" files inside the plugins directory of a notepad++ installation by a process other than "gup.exe". Which could indicates possible persistence

Event coverage

ProviderEvent IDTitle
Sysmon11FileCreate

Stages and Predicates

Stage 1: selection

TargetFilename|endswith: .dll
TargetFilename|contains: '\Notepad++\plugins\'

Stage 2: not 1 of filter_*

or:
or:
Image|endswith: Installer.x64.exe
Image|endswith: '\target.exe'
Image|contains: '\AppData\Local\Temp\'
Image|startswith: 'C:\Users\'
TargetFilename: ['C:\Program Files\Notepad++\plugins\Config\nppPluginList.dll', 'C:\Program Files\Notepad++\plugins\NppConverter\NppConverter.dll', 'C:\Program Files\Notepad++\plugins\NppExport\NppExport.dll', 'C:\Program Files\Notepad++\plugins\mimeTools\mimeTools.dll']
Image|endswith: .exe
Image|contains: '\npp.'
Image|endswith: '\Notepad++\updater\gup.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
  • .exe corpus 4 (sigma 4)
  • Installer.x64.exe
  • \Notepad++\updater\gup.exe
  • \target.exe
Imagematch
  • \AppData\Local\Temp\ corpus 9 (sigma 9)
  • \npp.
Imagestarts_with
  • C:\Users\ corpus 7 (sigma 7)
TargetFilenameends_with
  • .dll corpus 21 (sigma 21)
TargetFilenameeq
  • C:\Program Files\Notepad++\plugins\Config\nppPluginList.dll
  • C:\Program Files\Notepad++\plugins\NppConverter\NppConverter.dll
  • C:\Program Files\Notepad++\plugins\NppExport\NppExport.dll
  • C:\Program Files\Notepad++\plugins\mimeTools\mimeTools.dll
TargetFilenamematch
  • \Notepad++\plugins\