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Detection rules › Sigma

Potential Persistence Via Netsh Helper DLL

Status
test
Severity
medium
Log source
product windows, category process_creation
Author
Victor Sergeev, oscd.community
Source
github.com/SigmaHQ/sigma

Detects the execution of netsh with "add helper" flag in order to add a custom helper DLL. This technique can be abused to add a malicious helper DLL that can be used as a persistence proxy that gets called when netsh.exe is executed.

MITRE ATT&CK coverage

TacticTechniques
PersistenceT1546.007 Event Triggered Execution: Netsh Helper DLL
Privilege EscalationT1546.007 Event Triggered Execution: Netsh Helper DLL

Event coverage

ProviderEventTitle
SysmonEvent ID 1Process creation

Rule body yaml

title: Potential Persistence Via Netsh Helper DLL
id: 56321594-9087-49d9-bf10-524fe8479452
related:
    - id: c90362e0-2df3-4e61-94fe-b37615814cb1
      type: similar
    - id: e7b18879-676e-4a0e-ae18-27039185a8e7
      type: similar
status: test
description: |
    Detects the execution of netsh with "add helper" flag in order to add a custom helper DLL. This technique can be abused to add a malicious helper DLL that can be used as a persistence proxy that gets called when netsh.exe is executed.
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1546.007/T1546.007.md
    - https://github.com/outflanknl/NetshHelperBeacon
    - https://web.archive.org/web/20160928212230/https://www.adaptforward.com/2016/09/using-netshell-to-execute-evil-dlls-and-persist-on-a-host/
author: Victor Sergeev, oscd.community
date: 2019-10-25
modified: 2023-11-28
tags:
    - attack.privilege-escalation
    - attack.persistence
    - attack.t1546.007
    - attack.s0108
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        - OriginalFileName: 'netsh.exe'
        - Image|endswith: '\netsh.exe'
    selection_cli:
        CommandLine|contains|all:
            - 'add'
            - 'helper'
    condition: all of selection_*
falsepositives:
    - Unknown
level: medium

Stages and Predicates

Stage 0: condition

all of selection_*

Stage 1: selection_img

selection_img:
    - OriginalFileName: 'netsh.exe'
    - Image|endswith: '\netsh.exe'

Stage 2: selection_cli

selection_cli:
    CommandLine|contains|all:
        - 'add'
        - 'helper'

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
CommandLinematch
  • add corpus 34 (sigma 26, splunk 4, chronicle 2, kusto 2)
  • helper corpus 2 (sigma 2)
Imageends_with
  • \netsh.exe corpus 28 (sigma 28)
OriginalFileNameeq
  • netsh.exe corpus 23 (sigma 14, splunk 7, elastic 2)