Managing Policies

PSFalcon enables comprehensive management of CrowdStrike Falcon security policies, including Prevention, Response, Sensor Update, Firewall, and Device Control policies.

Policy Types

Falcon uses several policy types to control sensor behavior:

Prevention

Malware prevention, exploit blocking, and behavioral analysis settings

Response

Real-Time Response access and script execution permissions

Sensor Update

Sensor version deployment and update scheduling

Firewall

Network firewall rules and configurations

Device Control

USB and peripheral device access controls

Prevention Policies

Search and Retrieve Policies

# List all prevention policies
Get-FalconPreventionPolicy -All

# Get detailed policy information
Get-FalconPreventionPolicy -Detailed -All

# Search by name
Get-FalconPreventionPolicy -Filter "name:'Production*'" -Detailed

# Get policy by ID
$Policy = Get-FalconPreventionPolicy -Id 'abc123def456789012345678901234ab'

Create Prevention Policy

# Create a new prevention policy
$NewPolicy = New-FalconPreventionPolicy -Name 'Strict Prevention' `
  -PlatformName Windows `
  -Description 'High security settings for production servers'

Write-Host "Created policy: $($NewPolicy.id)"

Modify Prevention Settings

# Get current policy settings
$Policy = Get-FalconPreventionPolicy -Id $PolicyId

# Update policy settings
$Settings = @(
    @{ id = 'detection'; value = @{ enabled = $true } }
    @{ id = 'prevention'; value = @{ enabled = $true } }
    @{ id = 'AdwarePUP'; value = @{ enabled = $true; detection = 'MODERATE' } }
    @{ id = 'OnSensorMLSlider'; value = @{ detection = 'AGGRESSIVE'; prevention = 'AGGRESSIVE' } }
)

Edit-FalconPreventionPolicy -Id $PolicyId -Setting $Settings

Common Prevention Settings

# Enable aggressive malware detection
$Settings = @(
    @{ id = 'detection'; value = @{ enabled = $true } }
    @{ id = 'prevention'; value = @{ enabled = $true } }
    @{ id = 'OnSensorMLSlider'; value = @{ 
        detection = 'AGGRESSIVE'
        prevention = 'AGGRESSIVE' 
    }}
)

Edit-FalconPreventionPolicy -Id $PolicyId -Setting $Settings

Response Policies

Control Real-Time Response access for hosts:

# List response policies
Get-FalconResponsePolicy -Detailed -All

# Create new response policy
$ResponsePolicy = New-FalconResponsePolicy -Name 'IR Team RTR Access' `
  -PlatformName Windows `
  -Description 'RTR access for incident response team'

# Update response policy settings
$Settings = @(
    @{ id = 'real_time_response'; value = @{ enabled = $true } }
)

Edit-FalconResponsePolicy -Id $ResponsePolicy.id -Setting $Settings

Sensor Update Policies

Manage sensor version deployment:

# Get available sensor versions
Get-FalconSensorUpdateKernel -Filter "platform:'Windows'" -Detailed

# Create sensor update policy
$UpdatePolicy = New-FalconSensorUpdatePolicy -Name 'Staged Rollout' `
  -PlatformName Windows `
  -Description 'Gradual sensor updates'

# Configure update schedule
$Settings = @(
    @{ 
        id = 'scheduler' 
        value = @{ 
            enabled = $true
            timezone = 'America/New_York'
            day_of_week = @('Monday', 'Wednesday')
            time_of_day = '02:00'
        } 
    }
)

Edit-FalconSensorUpdatePolicy -Id $UpdatePolicy.id -Setting $Settings

Firewall Management Policies

# List firewall policies
Get-FalconFirewallPolicy -Detailed -All

# Create firewall policy
$FwPolicy = New-FalconFirewallPolicy -Name 'Server Firewall Rules' `
  -PlatformName Windows `
  -Description 'Custom firewall rules for servers'

# Get firewall rule groups
Get-FalconFirewallGroup -Detailed -All

Device Control Policies

Manage USB and peripheral device access:

# List device control policies
Get-FalconDeviceControlPolicy -Detailed -All

# Create device control policy
$DcPolicy = New-FalconDeviceControlPolicy -Name 'USB Restrictions' `
  -PlatformName Windows `
  -Description 'Block unauthorized USB devices'

# Configure USB blocking
$Settings = @(
    @{ 
        id = 'usb_mass_storage'
        value = @{ enabled = $true; action = 'FULL_ACCESS' }
    }
)

Edit-FalconDeviceControlPolicy -Id $DcPolicy.id -Setting $Settings

Policy Assignment

Assign Policies to Host Groups

# Get host group
$Group = Get-FalconHostGroup -Filter "name:'Production Servers'"

# Assign prevention policy to group
Invoke-FalconPreventionPolicyAction -Name assign `
  -Id $PreventionPolicyId `
  -GroupId $Group.id

# Assign multiple policies
$Policies = @{
    Prevention = $PreventionPolicyId
    Response = $ResponsePolicyId
    SensorUpdate = $SensorUpdatePolicyId
}

Invoke-FalconPreventionPolicyAction -Name assign -Id $Policies.Prevention -GroupId $Group.id
Invoke-FalconResponsePolicyAction -Name assign -Id $Policies.Response -GroupId $Group.id
Invoke-FalconSensorUpdatePolicyAction -Name assign -Id $Policies.SensorUpdate -GroupId $Group.id

View Policy Members

# Get hosts assigned to a policy
Get-FalconPreventionPolicyMember -Id $PolicyId -Detailed -All

# Include members when retrieving policy
Get-FalconPreventionPolicy -Id $PolicyId -Include members

Policy Precedence

When a host belongs to multiple groups with different policies, precedence determines which policy applies:

# Set policy precedence (lower number = higher priority)
Set-FalconPreventionPrecedence -PlatformName Windows `
  -Id @('policy1', 'policy2', 'policy3')

# View current precedence
Get-FalconPreventionPolicy -Filter "platform_name:'Windows'" `
  -Sort precedence.asc `
  -Detailed

Policies with precedence value 1 take highest priority. Default policies have the lowest precedence.

Policy Exclusions

ML Exclusions

# Create ML exclusion
New-FalconMlExclusion -Value 'C:\\TrustedApp\\*.exe' `
  -GroupId @($GroupId) `
  -Comment 'Exclude trusted application'

# List ML exclusions
Get-FalconMlExclusion -Detailed -All

# Remove ML exclusion
Remove-FalconMlExclusion -Id $ExclusionId

IOA Exclusions

# Create IOA exclusion pattern
$Pattern = @{
    name = 'cl_fsevent_ExternalMediaFileWritten'
    value = 'E:\\Backup\\*'
}

New-FalconIoaExclusion -PatternName $Pattern.name `
  -PatternId $Pattern.value `
  -GroupId @($GroupId) `
  -Comment 'Exclude backup drive activity'

# List IOA exclusions
Get-FalconIoaExclusion -Detailed -All

Sensor Visibility Exclusions

# Create SV exclusion
New-FalconSvExclusion -Value 'C:\\AppData\\*.tmp' `
  -GroupId @($GroupId) `
  -Comment 'Exclude temp files from visibility'

# List SV exclusions
Get-FalconSvExclusion -Detailed -All

Policy Management Workflow

Create Host Groups

# Create groups for different environments
New-FalconHostGroup -GroupType dynamic -Name 'Production Servers' `
  -AssignmentRule "platform_name:'Windows'+product_type_desc:'Server'+tags:'Production'"

New-FalconHostGroup -GroupType dynamic -Name 'Development Workstations' `
  -AssignmentRule "platform_name:'Windows'+product_type_desc:'Workstation'+tags:'Dev'"

Create Policies

# Create prevention policies for each environment
$ProdPolicy = New-FalconPreventionPolicy -Name 'Production - Strict' `
  -PlatformName Windows -Description 'High security for production'

$DevPolicy = New-FalconPreventionPolicy -Name 'Development - Moderate' `
  -PlatformName Windows -Description 'Balanced security for development'

Configure Settings

# Apply strict settings to production
$StrictSettings = @(
    @{ id = 'detection'; value = @{ enabled = $true } }
    @{ id = 'prevention'; value = @{ enabled = $true } }
    @{ id = 'OnSensorMLSlider'; value = @{ detection = 'AGGRESSIVE'; prevention = 'AGGRESSIVE' } }
)

Edit-FalconPreventionPolicy -Id $ProdPolicy.id -Setting $StrictSettings

Assign to Groups

# Get groups
$ProdGroup = Get-FalconHostGroup -Filter "name:'Production Servers'"
$DevGroup = Get-FalconHostGroup -Filter "name:'Development Workstations'"

# Assign policies
Invoke-FalconPreventionPolicyAction -Name assign -Id $ProdPolicy.id -GroupId $ProdGroup.id
Invoke-FalconPreventionPolicyAction -Name assign -Id $DevPolicy.id -GroupId $DevGroup.id

Add Exclusions

# Add necessary exclusions for dev environment
New-FalconMlExclusion -Value 'C:\\DevTools\\*.exe' `
  -GroupId @($DevGroup.id) `
  -Comment 'Development tools exclusion'

Verify Assignments

# Check policy members
Get-FalconPreventionPolicyMember -Id $ProdPolicy.id -Detailed | Measure-Object
Get-FalconPreventionPolicyMember -Id $DevPolicy.id -Detailed | Measure-Object

Best Practices

Test Before Production: Always test new policies in a development or staging environment before deploying to production hosts.

Use dynamic host groups with FQL rules for automatic policy assignment
Implement a precedence strategy to handle overlapping group membership
Document exclusions with clear comments explaining their purpose
Regularly audit policy assignments to ensure proper coverage
Use sensor update policies to control rollout timing and minimize impact

Bulk Policy Operations

# Clone policy settings to new policy
$SourcePolicy = Get-FalconPreventionPolicy -Id $SourcePolicyId
$NewPolicy = New-FalconPreventionPolicy -Name 'Cloned Policy' `
  -PlatformName $SourcePolicy.platform_name `
  -Description "Cloned from $($SourcePolicy.name)"

# Copy settings
Edit-FalconPreventionPolicy -Id $NewPolicy.id -Setting $SourcePolicy.prevention_settings.settings

# Bulk disable policies
$PoliciesToDisable = Get-FalconPreventionPolicy -Filter "name:*'Old'*"
foreach ($Policy in $PoliciesToDisable) {
    Invoke-FalconPreventionPolicyAction -Name disable -Id $Policy.id
}

Get Started

Core Concepts

Guides

Managing Policies

Policy Types

Prevention

Response

Sensor Update

Firewall

Device Control

Prevention Policies

Search and Retrieve Policies

Create Prevention Policy

Modify Prevention Settings

Common Prevention Settings

Response Policies

Sensor Update Policies

Firewall Management Policies

Device Control Policies

Policy Assignment

Assign Policies to Host Groups

View Policy Members

Policy Precedence

Policy Exclusions

ML Exclusions

IOA Exclusions

Sensor Visibility Exclusions

Policy Management Workflow

Best Practices

Bulk Policy Operations

Next Steps

Working with Hosts

Threat Intelligence

Build docs developers (and LLMs) love

Get Started

Core Concepts

Guides

​Policy Types

Prevention

Response

Sensor Update

Firewall

Device Control

​Prevention Policies

​Search and Retrieve Policies

​Create Prevention Policy

​Modify Prevention Settings

​Common Prevention Settings

​Response Policies

​Sensor Update Policies

​Firewall Management Policies

​Device Control Policies

​Policy Assignment

​Assign Policies to Host Groups

​View Policy Members

​Policy Precedence

​Policy Exclusions

​ML Exclusions

​IOA Exclusions

​Sensor Visibility Exclusions

​Policy Management Workflow

​Best Practices

​Bulk Policy Operations

​Next Steps

Working with Hosts

Threat Intelligence

Build docs developers (and LLMs) love

Policy Types

Prevention Policies

Search and Retrieve Policies

Create Prevention Policy

Modify Prevention Settings

Common Prevention Settings

Response Policies

Sensor Update Policies

Firewall Management Policies

Device Control Policies

Policy Assignment

Assign Policies to Host Groups

View Policy Members

Policy Precedence

Policy Exclusions

ML Exclusions

IOA Exclusions

Sensor Visibility Exclusions

Policy Management Workflow

Best Practices

Bulk Policy Operations

Next Steps