Detection rules › Sigma

Potential DLL Sideloading Using Coregen.exe

Severity
medium
Author
frack113
Source
upstream

Detect usage of the "coregen.exe" (Microsoft CoreCLR Native Image Generator) binary to sideload arbitrary DLLs.

MITRE ATT&CK coverage

TacticTechniques
Privilege EscalationT1055 Process Injection
Defense EvasionT1055 Process Injection, T1218 System Binary Proxy Execution

Event coverage

ProviderEvent IDTitle
Sysmon7Image loaded

Stages and Predicates

Stage 1: selection

Image|endswith: '\coregen.exe'

Stage 2: not 1 of filter_main_legit_paths

or:
ImageLoaded|startswith: 'C:\Program Files (x86)\Microsoft Silverlight\'
ImageLoaded|startswith: 'C:\Program Files\Microsoft Silverlight\'
ImageLoaded|startswith: 'C:\Windows\SysWOW64\'
ImageLoaded|startswith: 'C:\Windows\System32\'

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
  • \coregen.exe
ImageLoadedstarts_with
  • C:\Program Files (x86)\Microsoft Silverlight\
  • C:\Program Files\Microsoft Silverlight\
  • C:\Windows\SysWOW64\ corpus 8 (sigma 8)
  • C:\Windows\System32\ corpus 8 (sigma 8)