Detection rules › Sigma

DLL Load By System Process From Suspicious Locations

Status
test
Severity
medium
Log source
product windows, category image_load
Author
Nasreddine Bencherchali (Nextron Systems)
Source
github.com/SigmaHQ/sigma

Detects when a system process (i.e. located in system32, syswow64, etc.) loads a DLL from a suspicious location or a location with permissive permissions such as "C:\Users\Public"

MITRE ATT&CK coverage

TacticTechniques
StealthT1070 Indicator Removal

Event coverage

ProviderEventTitle
SysmonEvent ID 7Image loaded

Rule body yaml

title: DLL Load By System Process From Suspicious Locations
id: 9e9a9002-56c4-40fd-9eff-e4b09bfa5f6c
status: test
description: Detects when a system process (i.e. located in system32, syswow64, etc.) loads a DLL from a suspicious location or a location with permissive permissions such as "C:\Users\Public"
references:
    - https://github.com/hackerhouse-opensource/iscsicpl_bypassUAC (Idea)
author: Nasreddine Bencherchali (Nextron Systems)
date: 2022-07-17
modified: 2023-09-18
tags:
    - attack.stealth
    - attack.t1070
logsource:
    product: windows
    category: image_load
detection:
    selection:
        Image|startswith: 'C:\Windows\'
        ImageLoaded|startswith:
            # TODO: Add more suspicious paths as you see fit in your env
            - 'C:\Users\Public\'
            - 'C:\PerfLogs\'
    condition: selection
falsepositives:
    - Unknown
level: medium

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    Image|startswith: 'C:\Windows\'
    ImageLoaded|startswith:
        - 'C:\Users\Public\'
        - 'C:\PerfLogs\'

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
Imagestarts_with
  • C:\Windows\ corpus 2 (sigma 1, elastic 1)
ImageLoadedstarts_with
  • C:\PerfLogs\
  • C:\Users\Public\