Detection rules › Sigma

Suspicious Unsigned Dbghelp/Dbgcore DLL Loaded

Severity
high
Author
Perez Diego (@darkquassar), oscd.community, Ecco
Source
upstream

Detects the load of dbghelp/dbgcore DLL (used to make memory dumps) by suspicious processes. Tools like ProcessHacker and some attacker tradecract use MiniDumpWriteDump API found in dbghelp.dll or dbgcore.dll. As an example, SilentTrynity C2 Framework has a module that leverages this API to dump the contents of Lsass.exe and transfer it over the network back to the attacker's machine.

MITRE ATT&CK coverage

TacticTechniques
Credential AccessT1003.001 OS Credential Dumping: LSASS Memory

Event coverage

ProviderEvent IDTitle
Sysmon7Image loaded

Stages and Predicates

Stage 1: selection

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

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
ImageLoadedends_with
  • \dbgcore.dll corpus 4 (sigma 4)
  • \dbghelp.dll corpus 4 (sigma 4)
Signedeq
  • false corpus 8 (sigma 4, splunk 4)