Detection rules › Sigma

WinSxS Executable File Creation By Non-System Process

Severity
medium
Author
Nasreddine Bencherchali (Nextron Systems)
Source
upstream

Detects the creation of binaries in the WinSxS folder by non-system processes

Event coverage

ProviderEvent IDTitle
Sysmon11FileCreate

Stages and Predicates

Stage 1: selection

TargetFilename|endswith: .exe
TargetFilename|startswith: 'C:\Windows\WinSxS\'

Stage 2: not 1 of filter_main_system_location

or:
Image|startswith: 'C:\Windows\SysWOW64\'
Image|startswith: 'C:\Windows\Systems32\'
Image|startswith: 'C:\Windows\WinSxS\'

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
Imagestarts_with
  • C:\Windows\SysWOW64\ corpus 16 (sigma 16)
  • C:\Windows\Systems32\
  • C:\Windows\WinSxS\ corpus 13 (sigma 13)
TargetFilenameends_with
  • .exe corpus 18 (sigma 18)
TargetFilenamestarts_with
  • C:\Windows\WinSxS\ corpus 2 (sigma 2)