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Rewrite New-CBArraySplit, minor tweaks elsewhere. #1

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142 changes: 82 additions & 60 deletions DeployCryptoBlocker.ps1
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Original file line number Diff line number Diff line change
Expand Up @@ -2,66 +2,96 @@
#
################################ Functions ################################

function ConvertFrom-Json20([Object] $obj)
Function ConvertFrom-Json20
{
# Deserializes JSON input into PowerShell object output
Param (
[Object] $obj
)
Add-Type -AssemblyName System.Web.Extensions
$serializer = New-Object System.Web.Script.Serialization.JavaScriptSerializer
return ,$serializer.DeserializeObject($obj)
}

Function New-CBArraySplit {

Function New-CBArraySplit
{
<#
Takes an array of file extensions and checks if they would make a string >4Kb,
if so, turns it into several arrays
#>
param(
$extArr,
$depth = 1
$Extensions
)

$extArr = $extArr | Sort-Object -Unique

# Concatenate the input array
$conStr = $extArr -join ','
$outArr = @()

# If the input string breaks the 4Kb limit
If ($conStr.Length -gt 4096) {
# Pull the first 4096 characters and split on comma
$conArr = $conStr.SubString(0,4096).Split(',')
# Find index of the last guaranteed complete item of the split array in the input array
$endIndex = [array]::IndexOf($extArr,$conArr[-2])
# Build shorter array up to that indexNumber and add to output array
$shortArr = $extArr[0..$endIndex]
$outArr += [psobject] @{
index = $depth
array = $shortArr
}
$Extensions = $Extensions | Sort-Object -Unique

$workingArray = @()
$WorkingArrayIndex = 1
$LengthOfStringsInWorkingArray = 0

# TODO - is the FSRM limit for bytes or characters?
# maybe [System.Text.Encoding]::UTF8.GetBytes($_).Count instead?
# -> in case extensions have Unicode characters in them
# and the character Length is <4Kb but the byte count is >4Kb

# Take the items from the input array and build up a
# temporary workingarray, tracking the length of the items in it and future commas
$Extensions | ForEach-Object {

if (($LengthOfStringsInWorkingArray + 1 + $_.Length) -gt 4096)
{
# Adding this item to the working array (with +1 for a comma)
# pushes the contents past the 4Kb limit
# so output the workingArray
[PSCustomObject]@{
index = $WorkingArrayIndex
FileGroupName = "$Script:FileGroupName$WorkingArrayIndex"
array = $workingArray
}

# and reset the workingArray and counters
$workingArray = @($_) # new workingArray with current Extension in it
$LengthOfStringsInWorkingArray = $_.Length
$WorkingArrayIndex++

# Then call this function again to split further
$newArr = $extArr[($endindex + 1)..($extArr.Count -1)]
$outArr += New-CBArraySplit $newArr -depth ($depth + 1)

return $outArr
}
else #adding this item to the workingArray is fine
{
$workingArray += $_
$LengthOfStringsInWorkingArray += (1 + $_.Length) #1 for imaginary joining comma
}
}
# If the concat string is less than 4096 characters already, just return the input array
Else {
return [psobject] @{
index = $depth
array = $extArr
}

# The last / only workingArray won't have anything to push it past 4Kb
# and trigger outputting it, so output that one as well
[PSCustomObject]@{
index = ($WorkingArrayIndex)
FileGroupName = "$Script:FileGroupName$WorkingArrayIndex"
array = $workingArray
}
}

################################ Functions ################################

# Add to all drives
$drivesContainingShares = Get-WmiObject Win32_Share | Select Name,Path,Type | Where-Object { $_.Type -eq 0 } | Select -ExpandProperty Path | % { "$((Get-Item -ErrorAction SilentlyContinue $_).Root)" } | Select -Unique
if ($drivesContainingShares -eq $null -or $drivesContainingShares.Length -eq 0)
# Get all drives with shared folders, these drives will get FRSRM protection
$DrivesContainingShares = @(Get-WmiObject Win32_Share | # all shares on this computer, filter:
Where-Object { $_.Type -eq 0 } | # 0 = disk drives (not printers, IPC$, C$ Admin shares)
Selec-Object -ExpandProperty Path | # Shared folder path, e.g. "D:\UserFolders\"
ForEach-Object {
([System.IO.DirectoryInfo]$_).Root.Name # Extract the driveletter, as a string
} | Sort-Object -Unique) # remove duplicates


if ($drivesContainingShares.Count -eq 0)
{
Write-Host "No drives containing shares were found. Exiting.."
exit
}

Write-Host "The following shares needing to be protected: $($drivesContainingShares -Join ",")"


#### Identify Windows Server version, and install FSRM role
$majorVer = [System.Environment]::OSVersion.Version.Major
$minorVer = [System.Environment]::OSVersion.Version.Minor

Expand Down Expand Up @@ -95,32 +125,29 @@ if ($majorVer -ge 6)
else
{
# Assume Server 2003
Write-Host "Other version of Windows detected! Quitting.."
Write-Host "Unsupported version of Windows detected! Quitting.."
return
}


$fileGroupName = "CryptoBlockerGroup"
$fileTemplateName = "CryptoBlockerTemplate"
$fileScreenName = "CryptoBlockerScreen"

# Download list of CryptoLocker file extensions
$webClient = New-Object System.Net.WebClient
$jsonStr = $webClient.DownloadString("https://fsrm.experiant.ca/api/v1/get")
$monitoredExtensions = @(ConvertFrom-Json20($jsonStr) | % { $_.filters })

$monitoredExtensions = @(ConvertFrom-Json20 $jsonStr | ForEach-Object { $_.filters })

If (TestPath .\SkipList.txt) {
$exclusions = Get-Content .\SkipList.txt
ForEach ($exclusion in $exclusions) {
if ($exclusion) {
$monitoredExtensions = $monitoredExtensions.replace($exclusion.trim(),$null)
}
}
If (TestPath .\SkipList.txt)
{
$Exclusions = Get-Content .\SkipList.txt | ForEach-Object { $_.Trim() }
$monitoredExtensions = $monitoredExtensions | Where-Object { $Exclusions -notcontains $_ }
}
Else
{
$emptyFile = `
`
"#
$emptyFile = @'
#
# Add one filescreen per line that you want to ignore
#
# For example, if *.doc files are being blocked by the list but you want
Expand All @@ -132,18 +159,13 @@ Else
# The script will check this file every time it runs and remove these
# entries before applying the list to your FSRM implementation.
#

"
Add-Content .\SkipList.txt $emptyFile

'@
Set-Content -Path .\SkipList.txt -Value $emptyFile
}


# Split the $monitoredExtensions array into fileGroups of less than 4kb to allow processing by filescrn.exe
$fileGroups = New-CBArraySplit $monitoredExtensions
ForEach ($group in $fileGroups) {
$group | Add-Member -MemberType NoteProperty -Name fileGroupName -Value "$FileGroupName$($group.index)"
}
$fileGroups = @(New-CBArraySplit $monitoredExtensions)

# Perform these steps for each of the 4KB limit split fileGroups
ForEach ($group in $fileGroups) {
Expand All @@ -155,15 +177,15 @@ ForEach ($group in $fileGroups) {
Write-Host "Adding/replacing File Screen Template [$fileTemplateName] with Event Notification [$eventConfFilename] and Command Notification [$cmdConfFilename].."
&filescrn.exe Template Delete /Template:$fileTemplateName /Quiet
# Build the argument list with all required fileGroups
$screenArgs = 'Template','Add',"/Template:$fileTemplateName"
$screenArgs = 'Template', 'Add', "/Template:$fileTemplateName"
ForEach ($group in $fileGroups) {
$screenArgs += "/Add-Filegroup:$($group.fileGroupName)"
}

&filescrn.exe $screenArgs

Write-Host "Adding/replacing File Screens.."
$drivesContainingShares | % {
$drivesContainingShares | ForEach-Object {
Write-Host "`tAdding/replacing File Screen for [$_] with Source Template [$fileTemplateName].."
&filescrn.exe Screen Delete "/Path:$_" /Quiet
&filescrn.exe Screen Add "/Path:$_" "/SourceTemplate:$fileTemplateName"
Expand Down