Detection rules › Sigma

Potential Rcdll.DLL Sideloading

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

Detects potential DLL sideloading of rcdll.dll

MITRE ATT&CK coverage

Telemetry coverage

ProviderRecord / event type
SysmonEvent ID 7: Image loaded

Rule body

title: Potential Rcdll.DLL Sideloading
id: 6e78b74f-c762-4800-82ad-f66787f10c8a
status: test
description: Detects potential DLL sideloading of rcdll.dll
references:
    - https://www.trendmicro.com/en_us/research/23/c/iron-tiger-sysupdate-adds-linux-targeting.html
author: X__Junior (Nextron Systems)
date: 2023-03-13
modified: 2023-03-15
tags:
    - attack.persistence
    - attack.privilege-escalation
    - attack.execution
    - attack.stealth
    - attack.t1574.001
logsource:
    category: image_load
    product: windows
detection:
    selection:
        ImageLoaded|endswith: '\rcdll.dll'
    filter:
        ImageLoaded|startswith:
            - 'C:\Program Files (x86)\Microsoft Visual Studio\'
            - 'C:\Program Files (x86)\Windows Kits\'
    condition: selection and not filter
falsepositives:
    - Unknown
level: high

Stages and Predicates

Stage 0: condition

selection and not filter

Stage 1: selection

selection:
    ImageLoaded|endswith: '\rcdll.dll'

Stage 2: not filter

filter:
    ImageLoaded|startswith:
        - 'C:\Program Files (x86)\Microsoft Visual Studio\'
        - 'C:\Program Files (x86)\Windows Kits\'

Exclusions

The rule actively suppresses these predicates.

FieldKindExcluded valuesSearch
ImageLoadedstarts_withC:\Program Files (x86)\Microsoft Visual Studio\excludes:ImageLoaded field:"ImageLoaded" value:"C:\Program Files (x86)\Microsoft Visual Studio\"
ImageLoadedstarts_withC:\Program Files (x86)\Windows Kits\excludes:ImageLoaded field:"ImageLoaded" value:"C:\Program Files (x86)\Windows Kits\"

Indicators

These rows show field, operator, and value matches.