sigmahighHunting

Potential Attachment Manager Settings Associations Tamper

Detects tampering with attachment manager settings policies associations to lower the default file type risks (See reference for more information)

Detection Query

selection_main:
  TargetObject|contains: \SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\Associations\
selection_value_default_file_type_rsik:
  TargetObject|endswith: \DefaultFileTypeRisk
  Details: DWORD (0x00006152)
selection_value_low_risk_filetypes:
  TargetObject|endswith: \LowRiskFileTypes
  Details|contains:
    - .zip;
    - .rar;
    - .exe;
    - .bat;
    - .com;
    - .cmd;
    - .reg;
    - .msi;
    - .htm;
    - .html;
condition: selection_main and 1 of selection_value_*

Author

Nasreddine Bencherchali (Nextron Systems)

Created

2022-08-01

Data Sources

windowsRegistry Set Events

Platforms

windows

References

Tags

attack.defense-evasion

Raw Content

title: Potential Attachment Manager Settings Associations Tamper
id: a9b6c011-ab69-4ddb-bc0a-c4f21c80ec47
status: test
description: Detects tampering with attachment manager settings policies associations to lower the default file type risks (See reference for more information)
references:
    - https://support.microsoft.com/en-us/topic/information-about-the-attachment-manager-in-microsoft-windows-c48a4dcd-8de5-2af5-ee9b-cd795ae42738
    - https://www.virustotal.com/gui/file/2bcd5702a7565952c44075ac6fb946c7780526640d1264f692c7664c02c68465
author: Nasreddine Bencherchali (Nextron Systems)
date: 2022-08-01
modified: 2023-08-17
tags:
    - attack.defense-evasion
logsource:
    category: registry_set
    product: windows
detection:
    selection_main:
        TargetObject|contains: '\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\Associations\'
    selection_value_default_file_type_rsik:
        TargetObject|endswith: '\DefaultFileTypeRisk'
        Details: 'DWORD (0x00006152)'
    selection_value_low_risk_filetypes:
        TargetObject|endswith: '\LowRiskFileTypes'
        Details|contains: # Add more as you see fit
            - '.zip;'
            - '.rar;'
            - '.exe;'
            - '.bat;'
            - '.com;'
            - '.cmd;'
            - '.reg;'
            - '.msi;'
            - '.htm;'
            - '.html;'
    condition: selection_main and 1 of selection_value_*
falsepositives:
    - Unlikely
level: high