Detection rules › Sigma

Suspicious Loading of Dbgcore/Dbghelp DLLs from Uncommon Location

Severity
high
Author
Swachchhanda Shrawan Poudel (Nextron Systems)
Source
upstream

Detects loading of dbgcore.dll or dbghelp.dll from uncommon locations such as user directories. These DLLs contain the MiniDumpWriteDump function, which can be abused for credential dumping purposes or in some cases for evading EDR/AV detection by suspending processes.

MITRE ATT&CK coverage

TacticTechniques
Defense EvasionT1562.001 Impair Defenses: Disable or Modify Tools
Credential AccessT1003 OS Credential Dumping

Event coverage

ProviderEvent IDTitle
Sysmon7Image loaded

Stages and Predicates

Stage 1: all of selection_img

or:
Image|contains: ':\Perflogs\'
Image|contains: ':\Temp\'
Image|contains: ':\Users\Public\'
Image|contains: '\$Recycle.Bin\'
Image|contains: '\Contacts\'
Image|contains: '\Documents\'
Image|contains: '\Favorites\'
Image|contains: '\Favourites\'
Image|contains: '\Music\'
Image|contains: '\Pictures\'
Image|contains: '\Start Menu\Programs\Startup\'
Image|contains: '\Users\Default\'
Image|contains: '\Videos\'
Image|contains: '\inetpub\wwwroot\'

Stage 2: all of selection_dll

or:
ImageLoaded|endswith: '\dbgcore.dll'
ImageLoaded|endswith: '\dbghelp.dll'

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
Imagematch
  • :\Perflogs\ corpus 7 (sigma 7)
  • :\Temp\ corpus 12 (sigma 12)
  • :\Users\Public\ corpus 14 (sigma 14)
  • \$Recycle.Bin\ corpus 2 (sigma 2)
  • \Contacts\ corpus 5 (sigma 5)
  • \Documents\ corpus 2 (sigma 2)
  • \Favorites\ corpus 6 (sigma 6)
  • \Favourites\ corpus 5 (sigma 5)
  • \Music\ corpus 4 (sigma 4)
  • \Pictures\ corpus 5 (sigma 5)
  • \Start Menu\Programs\Startup\ corpus 2 (sigma 2)
  • \Users\Default\ corpus 4 (sigma 4)
  • \Videos\ corpus 4 (sigma 4)
  • \inetpub\wwwroot\ corpus 2 (sigma 2)
ImageLoadedends_with
  • \dbgcore.dll corpus 4 (sigma 4)
  • \dbghelp.dll corpus 4 (sigma 4)