Potential DLL Sideloading Of DBGHELP.DLL

Hunt Hypothesis

The hypothesis is that an adversary may be using DLL sideloading to inject malicious code through the DBGHELP.DLL library, leveraging its legitimate system usage to evade detection. SOC teams should proactively hunt for this behavior in Azure Sentinel to identify and mitigate potential code execution attacks that exploit trusted system components.

Detection Rule

Sigma (Original)

title: Potential DLL Sideloading Of DBGHELP.DLL
id: 6414b5cd-b19d-447e-bb5e-9f03940b5784
status: test
description: Detects potential DLL sideloading of "dbghelp.dll"
references:
    - https://hijacklibs.net/ # For list of DLLs that could be sideloaded (search for dlls mentioned here in there)
author: Nasreddine Bencherchali (Nextron Systems), Wietze Beukema (project and research)
date: 2022-10-25
modified: 2025-10-07
tags:
    - attack.defense-evasion
    - attack.persistence
    - attack.privilege-escalation
    - attack.t1574.001
logsource:
    category: image_load
    product: windows
detection:
    selection:
        ImageLoaded|endswith: '\dbghelp.dll'
    filter_main_generic:
        ImageLoaded|startswith:
            - 'C:\Program Files (x86)\'
            - 'C:\Program Files\'
            - 'C:\Windows\SoftwareDistribution\'
            - 'C:\Windows\System32\'
            - 'C:\Windows\SystemTemp\'
            - 'C:\Windows\SysWOW64\'
            - 'C:\Windows\WinSxS\'
    filter_optional_anaconda:
        ImageLoaded|endswith:
            - '\Anaconda3\Lib\site-packages\vtrace\platforms\windll\amd64\dbghelp.dll'
            - '\Anaconda3\Lib\site-packages\vtrace\platforms\windll\i386\dbghelp.dll'
    filter_optional_epicgames:
        ImageLoaded|endswith:
            - '\Epic Games\Launcher\Engine\Binaries\ThirdParty\DbgHelp\dbghelp.dll'
            - '\Epic Games\MagicLegends\x86\dbghelp.dll'
    filter_optional_opera:
        ImageLoaded|contains: 'opera\Opera Installer Temp\opera_package'
        ImageLoaded|endswith: '\assistant\dbghelp.dll'
    condition: selection and not 1 of filter_main_* and not 1 of filter_optional_*
falsepositives:
    - Legitimate applications loading their own versions of the DLL mentioned in this rule
level: medium

KQL (Microsoft 365 Defender)

DeviceImageLoadEvents
| where FolderPath endswith "\\dbghelp.dll" and (not((FolderPath startswith "C:\\Program Files (x86)\\" or FolderPath startswith "C:\\Program Files\\" or FolderPath startswith "C:\\Windows\\SoftwareDistribution\\" or FolderPath startswith "C:\\Windows\\System32\\" or FolderPath startswith "C:\\Windows\\SystemTemp\\" or FolderPath startswith "C:\\Windows\\SysWOW64\\" or FolderPath startswith "C:\\Windows\\WinSxS\\"))) and (not(((FolderPath endswith "\\Anaconda3\\Lib\\site-packages\\vtrace\\platforms\\windll\\amd64\\dbghelp.dll" or FolderPath endswith "\\Anaconda3\\Lib\\site-packages\\vtrace\\platforms\\windll\\i386\\dbghelp.dll") or (FolderPath endswith "\\Epic Games\\Launcher\\Engine\\Binaries\\ThirdParty\\DbgHelp\\dbghelp.dll" or FolderPath endswith "\\Epic Games\\MagicLegends\\x86\\dbghelp.dll") or (FolderPath contains "opera\\Opera Installer Temp\\opera_package" and FolderPath endswith "\\assistant\\dbghelp.dll"))))

False Positive Guidance

• Scenario: Debugging with WinDbg or Visual Studio
  Description: Developers or support engineers may load dbghelp.dll as part of debugging sessions using tools like WinDbg or Visual Studio.
  Filter/Exclusion: Check the process name (ProcessName field) for win_dbg.exe, devenv.exe, or vsdebugger.exe. Exclude processes associated with known debugging tools.

• Scenario: Scheduled System Maintenance or Patching
  Description: System administrators may use tools like schtasks.exe or task scheduler to run maintenance scripts that temporarily load dbghelp.dll for diagnostic purposes.
  Filter/Exclusion: Filter by ProcessName for schtasks.exe or taskhost.exe, and check for known administrative tasks or scripts that are part of routine maintenance.

• Scenario: Antivirus or Security Software Integration
  Description: Some security software may use dbghelp.dll for analysis or debugging during malware scanning or heuristic analysis.
  Filter/Exclusion: Check the parent process for known antivirus or endpoint protection software (e.g., mcafee.exe, avgnt.exe, bitdefender.exe) and exclude those processes.

• Scenario: PowerShell Scripting for Troubleshooting
  Description: IT staff may use PowerShell scripts to load dbghelp.dll for diagnostic purposes, such as analyzing crash dumps or system logs.
  Filter/Exclusion: Filter by ProcessName for powershell.exe and check for command-line arguments or script paths that are known to be part of legitimate troubleshooting activities.

• Scenario: Windows Update or System File Checker (SFC) Operations
  Description: During system updates or when running sfc /scannow, the system may temporarily load dbghelp.dll as part of the integrity check process.

MITRE ATT&CK Context

• Tactic: Defense Evasion
• Tactic: Persistence
• Tactic: Privilege Escalation
• Technique: T1574.001