Monitoring with PowerShell: Detecting Log4J files

Hey all, so this is a pretty quick one, to add onto the already many scripts released for this. In this script we’re trying to get all the files that could suffer from the Log4J issue in CVE-2021-44228. I’m saying could, because the script detects a class that is also used in other products, Hence it might end up with some minor false positives.

The script uses “Everything” by Voidtools which is a rapid search tool that can index all files on Windows much faster than anything else. I suggest you host the portable version somewhere yourself so you are able to control exactly which version get’s installed, and you can do your due diligence on there.

As always, I assume you are executing this script as system, from your RMM tooling.

$PortableEverythingURL = "https://www.voidtools.com/Everything-1.4.1.1009.x64.zip"

Set-PSRepository -Name 'PSGallery' -InstallationPolicy Trusted
Invoke-WebRequest -UseBasicParsing -Uri $PortableEverythingURL -OutFile "$($ENV:TEMP)\Everything.zip"
Expand-Archive "$($ENV:TEMP)\Everything.zip" -DestinationPath $($ENV:Temp) -Force
if (!(Get-Service "Everything Client" -ErrorAction SilentlyContinue)) {
& "$($ENV:TEMP)\everything.exe" -install-client-service
& "$($ENV:TEMP)\everything.exe" -reindex
start-sleep 3
Install-Module PSEverything
}
else {
& "$($ENV:TEMP)\everything.exe" -reindex
Install-Module PSEverything

}
$ScanResults = search-everything -global -extension jar
if ($ScanResults) {
Write-Host "Potential vulnerable JAR files found. Please investigate:"
Write-Host "all Results:"
$scanresults
    Write-Host "All Results with vulnerable class:"
($ScanResults | ForEach-Object { Select-String "JndiLookup.class" $\_ }).path
}
else {
Write-Host "Did not find any vulnerable files."
}

you can easily implement this script in most RMM systems, and get a quick overview of places you might have log4j active. This is just one of many solutions, Also check out some other solutions by one of my friends, Prejay Shah here. This one uses Search-Everything, but fails back to get-childitem if that is not working.

As always, Happy PowerShelling,.

Recent Articles

The return of CyberDrain CTF

CyberDrain CTF returns! (and so do I!)

It’s been since september that I actually picked up a digital pen equivalent and wrote anything down. This was due to me being busy with life but also my side projects like CIPP. I’m trying to get back into the game of scripting and blogging about these scripts. There’s still so much to automate and so little time, right? ;)

Monitoring with PowerShell: Monitoring Acronis Backups

Intro

This is a monitoring script requested via Reddit, One of the reddit r/msp users wondered how they can monitor Acronis a little bit easier. I jumped on this because it happened pretty much at the same time that I was asked to speak at the Acronis CyberSummit so it kinda made sense to script this so I have something to demonstrate at my session there.

Monitoring with PowerShell: Monitoring VSS Snapshots

Intro

Wow! It’s been a while since I’ve blogged. I’ve just been so swamped with CIPP that I’ve just let the blogging go entirely. It’s a shame because I think out of all my hobbies it’s one I enjoy the most. It’s always nice helping others achieve their scripting target. I even got a couple of LinkedIn questions asking if I was done with blogging but I’m not. Writing always gives me some more piece of mind so I’ll try to catch up again. I know I’ve said that before but this time I’ll follow through. I’m sitting down right now and scheduling the release of 5 blogs in one go. No more whining and no more waiting.