Suspicious GUP Usage

Hunt Hypothesis

Detects execution of the Notepad++ updater in a suspicious directory, which is often used in DLL side-loading attacks

Detection Rule

Sigma (Original)

title: Suspicious GUP Usage
id: 0a4f6091-223b-41f6-8743-f322ec84930b
status: test
description: Detects execution of the Notepad++ updater in a suspicious directory, which is often used in DLL side-loading attacks
references:
    - https://www.fireeye.com/blog/threat-research/2018/09/apt10-targeting-japanese-corporations-using-updated-ttps.html
author: Florian Roth (Nextron Systems)
date: 2019-02-06
modified: 2022-08-13
tags:
    - attack.privilege-escalation
    - attack.persistence
    - attack.execution
    - attack.stealth
    - attack.t1574.001
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith: '\GUP.exe'
    filter_programfiles:
        Image|endswith:
            - '\Program Files\Notepad++\updater\GUP.exe'
            - '\Program Files (x86)\Notepad++\updater\GUP.exe'
    filter_user:
        Image|contains: '\Users\'
        Image|endswith:
            - '\AppData\Local\Notepad++\updater\GUP.exe'
            - '\AppData\Roaming\Notepad++\updater\GUP.exe'
    condition: selection and not 1 of filter_*
falsepositives:
    - Execution of tools named GUP.exe and located in folders different than Notepad++\updater
level: high

KQL (Azure Sentinel)

imProcessCreate
| where TargetProcessName endswith "\\GUP.exe" and (not(((TargetProcessName endswith "\\Program Files\\Notepad++\\updater\\GUP.exe" or TargetProcessName endswith "\\Program Files (x86)\\Notepad++\\updater\\GUP.exe") or (TargetProcessName contains "\\Users\\" and (TargetProcessName endswith "\\AppData\\Local\\Notepad++\\updater\\GUP.exe" or TargetProcessName endswith "\\AppData\\Roaming\\Notepad++\\updater\\GUP.exe")))))

Required Data Sources

False Positive Guidance

• Execution of tools named GUP.exe and located in folders different than Notepad++\updater

MITRE ATT&CK Context

• Tactic: Privilege Escalation
• Tactic: Persistence
• Tactic: Execution
• Technique: T1574.001 — T1574.001

References

• https://www.fireeye.com/blog/threat-research/2018/09/apt10-targeting-japanese-corporations-using-updated-ttps.html
• SigmaHQ Rule