Potential JLI.dll Side-Loading

Description

Detects potential DLL side-loading of jli.dll. JLI.dll has been observed being side-loaded by Java processes by various threat actors, including APT41, XWorm, and others in order to load malicious payloads in context of legitimate Java processes.

Query · sigma

selection:
  ImageLoaded|endswith: \jli.dll
filter_main_legitimate_install_paths:
  ImageLoaded|startswith:
  - C:\Program Files\
  - C:\Program Files (x86)\
  Description: OpenJDK Platform binary
  OriginalFileName: jli.dll
  Product|startswith: OpenJDK Platform
  Signed: 'true'
filter_optional_eclipse:
  ImageLoaded|startswith: C:\eclipse\plugins\
condition: selection and not 1 of filter_main_* and not 1 of filter_optional_*

Known false positives

  • Unknown
Raw source Potential JLI.dll Side-Loading · Sigma
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Published by SigmaHQ/sigma ↗, licensed under Detection Rule License 1.1 ↗. Reproduced here unmodified. 
title: Potential JLI.dll Side-Loading
id: 7a3b6d1f-4a2b-4f8c-9d7e-e9f8cbf21a35
status: experimental
description: |
    Detects potential DLL side-loading of jli.dll.
    JLI.dll has been observed being side-loaded by Java processes by various threat actors, including APT41, XWorm,
    and others in order to load malicious payloads in context of legitimate Java processes.
references:
    - https://securelist.com/apt41-in-africa/116986/
    - https://lab52.io/blog/snake-keylogger-in-geopolitical-affairs-abuse-of-trusted-java-utilities-in-cybercrime-operations/
    - https://hijacklibs.net/entries/3rd_party/oracle/jli.html
    - https://www.proofpoint.com/us/blog/threat-insight/phish-china-aligned-espionage-actors-ramp-up-taiwan-semiconductor-targeting
author: Swachchhanda Shrawan Poudel (Nextron Systems)
date: 2025-07-25
modified: 2025-10-06
tags:
    - attack.persistence
    - attack.privilege-escalation
    - attack.execution
    - attack.stealth
    - attack.t1574.001
logsource:
    category: image_load
    product: windows
detection:
    selection:
        ImageLoaded|endswith: '\jli.dll'
    filter_main_legitimate_install_paths:
        ImageLoaded|startswith:
            # Keeping the paths generic as jli.dll was found inside various directories of installed software
            - 'C:\Program Files\'
            - 'C:\Program Files (x86)\'
        Description: 'OpenJDK Platform binary'
        OriginalFileName: 'jli.dll'
        Product|startswith: 'OpenJDK Platform'
        Signed: 'true'
    filter_optional_eclipse:
        ImageLoaded|startswith: 'C:\eclipse\plugins\'
    condition: selection and not 1 of filter_main_* and not 1 of filter_optional_*
falsepositives:
    - Unknown
level: high

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