Log4JShell-Bytecode-Detector VS CVE-2021-44228-Log4Shell-Hashes

To check if your jar file is affected by the critical CVE-2021-44228, we provide an open-source command line tool https://github.com/CodeShield-Security/Log4JShell-Bytecode-Detector. The tool scans the jar file and compares the classses against a set of pre-computed hashes of the vulnerable Log4j classes. Since our tool only uses the hash and fingerprints of bytecode classes, no source code needs to be available.

u/sanitybit My colleagues have written a detector for the vulnerability: https://github.com/CodeShield-Security/Log4JShell-Bytecode-Detector

[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12 $vulnerablesums = -split $(Invoke-WebRequest https://github.com/mubix/CVE-2021-44228-Log4Shell-Hashes/raw/main/sha256sums.txt -UseBasicParsing).content | ? {$_.length -eq 64} $localsums = $Null $DriveList = (Get-PSDrive -PSProvider FileSystem).Root ForEach($Drive In $DriveList) { $localfile=(get-childitem $Drive log4j*.jar -file -Recurse -erroraction silentlycontinue | Get-ItemProperty).DirectoryName $localsums=(get-childitem $Drive log4j*.jar -file -Recurse -erroraction silentlycontinue | Get-FileHash).hash ($localsums -and (compare-object -ReferenceObject $vulnerablesums -DifferenceObject $localsums -IncludeEqual -ErrorAction SilentlyContinue).SideIndicator -eq "==") Write-Host $localfile }

-split (Invoke-WebRequest https://github.com/mubix/CVE-2021-44228-Log4Shell-Hashes/raw/main/sha256sums.txt -UseBasicParsing).content | Where-Object {$_.length -eq 64}

#messy alphabet array [char[]]$driveletters = "ABCDEFGHIJKLMNOPQRSTUVWXYZ" #foreach letter of the alphabet foreach($driveletter in $driveletters) { #formats the variable because i'm bad $drive= "$driveletter"+":\" #if the drive letter exists and isn't just assigned to a dvd rive if(test-path $drive){ #creates the path to check for log4j files $log4jpath = "$drive"+"log4j*.jar" ###Get Vulnerable Hashes $vulnerablesums = -split $(Invoke-WebRequest https://github.com/mubix/CVE-2021-44228-Log4Shell-Hashes/raw/main/sha256sums.txt -UseBasicParsing).content | Where-Object {$_.length -eq 64} ###Get Hash and file location for each log4j*.jar file $localsums = get-childitem $log4jpath -file -Recurse | Select-Object Fullname, @{Name = "Hash"; Expression = {(Get-FileHash -Path $_.FullName).Hash}} ###If Log4j*.jar is found compare hash to bad hashes if(-not($null -eq $localsums)){$BadHash = Compare-Object -ReferenceObject $vulnerablesums -DifferenceObject $localsums.Hash -ExcludeDifferent -IncludeEqual -ErrorAction SilentlyContinue} ###Return FileLocation and hash for each vulnerable result foreach($Entry in $localsums){ if($BadHash.InputObject -contains $Entry.Hash){ $Entry } } } }

if you want to match for a single word inside the path like the programs folder name use -notmatch. $vulnerablesums = -split $(Invoke-WebRequest https://github.com/mubix/CVE-2021-44228-Log4Shell-Hashes/raw/main/sha256sums.txt -UseBasicParsing).content |Where-Object { $_.length -eq 64 } $localsums = (get-childitem -path "C:\" -file "log4j*.jar" -Recurse |Where-Object {$_.DirectoryName -notmatch "YOUR APPNAME"} | Get-FileHash).hash ($localsums -and (compare-object -ReferenceObject $vulnerablesums -DifferenceObject $localsums -IncludeEqual -ErrorAction SilentlyContinue).SideIndicator -eq "==") `

I think you mean vulnerable, but you can feed the jar file into get-filehash and see if it matches one listed as vulnerable here: https://github.com/mubix/CVE-2021-44228-Log4Shell-Hashes/blob/main/sha256sums.txt

How would i create a query to do a mass hash lookup per the log4j version hashes found here: https://github.com/mubix/CVE-2021-44228-Log4Shell-Hashes

For example search for the vulnerable files: https://github.com/mubix/CVE-2021-44228-Log4Shell-Hashes