private List <string> ConvertPayloadToStrings(byte[] shellcode, BaseNEncoder encoder)
{
List <string> output = new List <string>();
string encodedContent = "";
for (int offset = 0; offset < shellcode.Length; offset += 16)
{
byte[] guidShellcode;
if (shellcode.Length - offset < 16)
{
guidShellcode = shellcode.Skip(offset).ToArray();
Array.Resize(ref guidShellcode, 16);
}
else
{
guidShellcode = shellcode.Skip(offset).Take(16).ToArray();
}
string encodedGuid = encoder.Encode(guidShellcode);
encodedContent += encodedGuid;
if (encodedContent.Length > 200)
{
output.Add(encodedContent);
encodedContent = "";
}
}
if (encodedContent.Length > 0)
{
output.Add(encodedContent);
}
return(output);
}
public void TestBase255EncodingForEdgeCasePayloads()
{
byte[] shellcode = new byte[] { 0x00, 0x01, 0x02, 0x03, 0xFC, 0xFD, 0xFE, 0xFF };
BaseNEncoder encoder = new BaseNEncoder();
Console.WriteLine(encoder);
string encodedShellcode = encoder.Encode(shellcode);
List <int> lookups = new List <int>();
foreach (var c in encodedShellcode)
{
lookups.Add((int)c);
}
int encodedLen = encodedShellcode.Length;
byte[] decodedShellcode = encoder.Decode(encodedShellcode);
Assert.AreEqual(shellcode, decodedShellcode);
}
public void TestBase255XorEncoding()
{
BaseNEncoder encoder = new BaseNEncoder();
byte[] nullShellcode = new byte[] { 0, 0, 0 };
string xorKey = "\x00\x00\x00";
byte[] xoredNullShellcode = XorPayloadAgainstString(nullShellcode, xorKey);
Assert.AreEqual(xorKey, Encoding.Default.GetString(xoredNullShellcode));
byte[] shellcode = TestHelpers.GetPopCalc64Shellcode();
shellcode = XorPayloadAgainstString(shellcode, xorKey);
// var strings = ConvertPayloadToStrings(shellcode, encoder);
var strings = FormulaHelper.BuildBase64PayloadMacros(shellcode);
foreach (var s in strings)
{
Console.WriteLine(string.Format("=\"{0}\"", s));
}
}
public void TestBase255EncodingForBasicPayload()
{
byte[] shellcode = TestHelpers.GetPopCalcShellcode();
BaseNEncoder encoder = new BaseNEncoder();
var strings = FormulaHelper.BuildBase64PayloadMacros(shellcode);
foreach (var s in strings)
{
Console.WriteLine(string.Format("=\"{0}\"", s));
}
string encodedShellcode = encoder.Encode(shellcode);
int encodedLen = encodedShellcode.Length;
byte[] decodedShellcode = encoder.Decode(encodedShellcode);
Assert.AreEqual(shellcode, decodedShellcode);
}
