Potential Attachment Manager Settings Attachments Tamper

Hunt Hypothesis

Detects tampering with attachment manager settings policies attachments (See reference for more information)

Detection Rule

Sigma (Original)

title: Potential Attachment Manager Settings Attachments Tamper
id: ee77a5db-b0f3-4be2-bfd4-b58be1c6b15a
status: test
description: Detects tampering with attachment manager settings policies attachments (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-impairment
logsource:
    category: registry_set
    product: windows
detection:
    selection_main:
        TargetObject|contains: '\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\Attachments\'
    selection_value_hide_zone_info:
        TargetObject|endswith: '\HideZoneInfoOnProperties'
        Details: 'DWORD (0x00000001)' # On
    selection_value_save_zone_info:
        TargetObject|endswith: '\SaveZoneInformation'
        Details: 'DWORD (0x00000002)' # Off
    selection_value_scan_with_av:
        TargetObject|endswith: '\ScanWithAntiVirus'
        Details: 'DWORD (0x00000001)' # Disabled
    condition: selection_main and 1 of selection_value_*
falsepositives:
    - Unlikely
level: high

KQL (Azure Sentinel)

imRegistry
| where RegistryKey endswith "\\SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Policies\\Attachments*" and ((RegistryKey endswith "\\HideZoneInfoOnProperties" and RegistryValueData =~ "DWORD (0x00000001)") or (RegistryKey endswith "\\SaveZoneInformation" and RegistryValueData =~ "DWORD (0x00000002)") or (RegistryKey endswith "\\ScanWithAntiVirus" and RegistryValueData =~ "DWORD (0x00000001)"))

KQL (Microsoft 365 Defender)

DeviceRegistryEvents
| where RegistryKey endswith "\\SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Policies\\Attachments*" and ((RegistryKey endswith "\\HideZoneInfoOnProperties" and RegistryValueData =~ "DWORD (0x00000001)") or (RegistryKey endswith "\\SaveZoneInformation" and RegistryValueData =~ "DWORD (0x00000002)") or (RegistryKey endswith "\\ScanWithAntiVirus" and RegistryValueData =~ "DWORD (0x00000001)"))

Required Data Sources

False Positive Guidance

• Unlikely

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
• SigmaHQ Rule