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Detection rules › Sigma

DLL Load via LSASS

Status
test
Severity
high
Log source
product windows, category registry_event
Author
Florian Roth (Nextron Systems)
Source
github.com/SigmaHQ/sigma

Detects a method to load DLL via LSASS process using an undocumented Registry key

MITRE ATT&CK coverage

TacticTechniques
PersistenceT1547.008 Boot or Logon Autostart Execution: LSASS Driver
Privilege EscalationT1547.008 Boot or Logon Autostart Execution: LSASS Driver

Event coverage

ProviderEventTitle
SysmonEvent ID 12RegistryEvent (Object create and delete)
SysmonEvent ID 13RegistryEvent (Value Set)
SysmonEvent ID 14RegistryEvent (Key and Value Rename)

Rule body yaml

title: DLL Load via LSASS
id: b3503044-60ce-4bf4-bbcb-e3db98788823
status: test
description: Detects a method to load DLL via LSASS process using an undocumented Registry key
references:
    - https://blog.xpnsec.com/exploring-mimikatz-part-1/
    - https://twitter.com/SBousseaden/status/1183745981189427200
author: Florian Roth (Nextron Systems)
date: 2019-10-16
modified: 2022-04-21
tags:
    - attack.privilege-escalation
    - attack.execution
    - attack.persistence
    - attack.t1547.008
logsource:
    category: registry_event
    product: windows
detection:
    selection:
        TargetObject|contains:
            - '\CurrentControlSet\Services\NTDS\DirectoryServiceExtPt'
            - '\CurrentControlSet\Services\NTDS\LsaDbExtPt'
    filter_domain_controller:
        Image: 'C:\Windows\system32\lsass.exe'
        Details:
            - '%%systemroot%%\system32\ntdsa.dll'
            - '%%systemroot%%\system32\lsadb.dll'
    condition: selection and not 1 of filter_*
falsepositives:
    - Unknown
level: high

Stages and Predicates

Stage 0: condition

selection and not 1 of filter_*

Stage 1: selection

selection:
    TargetObject|contains:
        - '\CurrentControlSet\Services\NTDS\DirectoryServiceExtPt'
        - '\CurrentControlSet\Services\NTDS\LsaDbExtPt'

Stage 2: not filter_domain_controller

filter_domain_controller:
    Image: 'C:\Windows\system32\lsass.exe'
    Details:
        - '%%systemroot%%\system32\ntdsa.dll'
        - '%%systemroot%%\system32\lsadb.dll'

Exclusions

Top-level NOT(...) conjuncts: predicates this rule actively suppresses.

FieldKindExcluded values
Detailseq%%systemroot%%\system32\lsadb.dll
Detailseq%%systemroot%%\system32\ntdsa.dll
ImageeqC:\Windows\system32\lsass.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
TargetObjectmatch
  • \CurrentControlSet\Services\NTDS\DirectoryServiceExtPt
  • \CurrentControlSet\Services\NTDS\LsaDbExtPt