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C# Memory Scanning

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KryziK
Expert Cheater

Reputation: 3

Joined: 16 Aug 2009
Posts: 199

Posted: Tue May 31, 2011 7:42 pm Post subject: C# Memory Scanning

Alright, so I've seen plenty of these posts on the forums, but I haven't found one with a straight up answer. Here is my code:

Code:

[DllImport("kernel32.dll")]
internal static extern Int32 VirtualQueryEx(IntPtr hProcess, IntPtr lpAddress, out Memory.MEMORY_BASIC_INFORMATION lpBuffer, uint dwLength);

private MEMORY_BASIC_INFORMATION MBI;

[StructLayout(LayoutKind.Sequential)]
public struct MEMORY_BASIC_INFORMATION
{
public IntPtr BaseAddress;
public IntPtr AllocationBase;
public uint AllocationProtect;
public IntPtr RegionSize;
public uint State;
public uint Protect;
public uint Type;
}

public int AOBScan(byte[] bBytesToSearch, long iStartAddress = 0, long iEndAddress = 0x7FFFFFFF)
{
long iAddress = iStartAddress; IntPtr ptrBytesRead; byte[] bBuffer;

do
{
   int iRead = API.VirtualQueryEx(hReadProcess, (IntPtr)iAddress, out MBI, (uint)Marshal.SizeOf(MBI));
   if ((iRead > 0) && ((int)MBI.RegionSize > 0))
   {
      bBuffer = new byte[(int)MBI.RegionSize];
      API.ReadProcessMemory(hReadProcess, MBI.BaseAddress, bBuffer, (uint)bBuffer.Length, out ptrBytesRead);
      //Search Buffer for specified bytes. Not included so I don't have to include the FindBytesinByteArray function.
   }
   iAddress = (long)(MBI.BaseAddress.ToInt64() + MBI.RegionSize.ToInt64());
} while (iAddress <= iEndAddress);
return 0;
}

To be clear, this code WORKS, however, I feel like I should add something to it to make it safer/easier to use/debug. I haven't included any Types like MEM_PRIVATE, etc., or States like MEM_COMMIT, etc.. Should these be added or should any additional checks be made within the function? Sorry if I'm being unclear. I'm simply asking if there's anything I've overlooked that I should include as a good practice.

Also, I've seen many different DLLImports for this function. This one seems to work while the others didn't, but just to make sure, is this correct, or will I somehow lose some data when it's in the wrong format? I'm more concerned about the struct than the import itself.

atom0s
Moderator

Reputation: 205

Joined: 25 Jan 2006
Posts: 8585
Location: 127.0.0.1

Posted: Wed Jun 01, 2011 11:48 am Post subject:

This is how I did it a while back:

Code:

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using Microsoft.Win32.SafeHandles;

//
// sigScan C# Implementation - Written by atom0s [aka Wiccaan]
// Class Version: 2.0.0
//
// [ CHANGE LOG ] -------------------------------------------------------------------------
//
// 2.0.0
// - Updated to no longer require unsafe or fixed code.
// - Removed unneeded methods and code.
//
// 1.0.0
// - First version written and release.
//
// [ CREDITS ] ----------------------------------------------------------------------------
//
// sigScan is based on the FindPattern code written by
// dom1n1k and Patrick at GameDeception.net
//
// Full credit to them for the purpose of this code. I, atom0s, simply
// take credit for converting it to C#.
//
// [ USAGE ] ------------------------------------------------------------------------------
//
// Examples:
//
// SigScan _sigScan = new SigScan();
// _sigScan.Process = someProc;
// _sigScan.Address = new IntPtr(0x123456);
// _sigScan.Size = 0x1000;
// IntPtr pAddr = _sigScan.FindPattern(new byte[]{ 0xFF, 0xFF, 0xFF, 0xFF, 0x51, 0x55, 0xFC, 0x11 }, "xxxx?xx?", 12);
//
// SigScan _sigScan = new SigScan(someProc, new IntPtr(0x123456), 0x1000);
// IntPtr pAddr = _sigScan.FindPattern(new byte[]{ 0xFF, 0xFF, 0xFF, 0xFF, 0x51, 0x55, 0xFC, 0x11 }, "xxxx?xx?", 12);
//
// ----------------------------------------------------------------------------------------
namespace SigScan.Classes
{
public class SigScan
{
/// <summary>
/// ReadProcessMemory
///
/// API import definition for ReadProcessMemory.
/// </summary>
/// <param name="hProcess">Handle to the process we want to read from.</param>
/// <param name="lpBaseAddress">The base address to start reading from.</param>
/// <param name="lpBuffer">The return buffer to write the read data to.</param>
/// <param name="dwSize">The size of data we wish to read.</param>
/// <param name="lpNumberOfBytesRead">The number of bytes successfully read.</param>
/// <returns></returns>
[DllImport("kernel32.dll", SetLastError = true)]
private static extern bool ReadProcessMemory(
IntPtr hProcess,
IntPtr lpBaseAddress,
[Out()] byte[] lpBuffer,
int dwSize,
out int lpNumberOfBytesRead
);

/// <summary>
/// m_vDumpedRegion
///
/// The memory dumped from the external process.
/// </summary>
private byte[] m_vDumpedRegion;

/// <summary>
/// m_vProcess
///
/// The process we want to read the memory of.
/// </summary>
private Process m_vProcess;

/// <summary>
/// m_vAddress
///
/// The starting address we want to begin reading at.
/// </summary>
private IntPtr m_vAddress;

/// <summary>
/// m_vSize
///
/// The number of bytes we wish to read from the process.
/// </summary>
private Int32 m_vSize;

#region "sigScan Class Construction"
/// <summary>
/// SigScan
///
/// Main class constructor that uses no params.
/// Simply initializes the class properties and
/// expects the user to set them later.
/// </summary>
public SigScan()
{
this.m_vProcess = null;
this.m_vAddress = IntPtr.Zero;
this.m_vSize = 0;
this.m_vDumpedRegion = null;
}
/// <summary>
/// SigScan
///
/// Overloaded class constructor that sets the class
/// properties during construction.
/// </summary>
/// <param name="proc">The process to dump the memory from.</param>
/// <param name="addr">The started address to begin the dump.</param>
/// <param name="size">The size of the dump.</param>
public SigScan(Process proc, IntPtr addr, int size)
{
this.m_vProcess = proc;
this.m_vAddress = addr;
this.m_vSize = size;
}
#endregion

#region "sigScan Class Private Methods"
/// <summary>
/// DumpMemory
///
/// Internal memory dump function that uses the set class
/// properties to dump a memory region.
/// </summary>
/// <returns>Boolean based on RPM results and valid properties.</returns>
private bool DumpMemory()
{
try
{
// Checks to ensure we have valid data.
if (this.m_vProcess == null)
return false;
if (this.m_vProcess.HasExited == true)
return false;
if (this.m_vAddress == IntPtr.Zero)
return false;
if (this.m_vSize == 0)
return false;

// Create the region space to dump into.
this.m_vDumpedRegion = new byte[this.m_vSize];

bool bReturn = false;
int nBytesRead = 0;

// Dump the memory.
bReturn = ReadProcessMemory(
this.m_vProcess.Handle, this.m_vAddress, this.m_vDumpedRegion, this.m_vSize, out nBytesRead
);

// Validation checks.
if (bReturn == false || nBytesRead != this.m_vSize)
return false;
return true;
}
catch (Exception ex)
{
return false;
}
}

/// <summary>
/// MaskCheck
///
/// Compares the current pattern byte to the current memory dump
/// byte to check for a match. Uses wildcards to skip bytes that
/// are deemed unneeded in the compares.
/// </summary>
/// <param name="nOffset">Offset in the dump to start at.</param>
/// <param name="btPattern">Pattern to scan for.</param>
/// <param name="strMask">Mask to compare against.</param>
/// <returns>Boolean depending on if the pattern was found.</returns>
private bool MaskCheck(int nOffset, byte[] btPattern, string strMask)
{
// Loop the pattern and compare to the mask and dump.
for (int x = 0; x < btPattern.Length; x++)
{
// If the mask char is a wildcard, just continue.
if (strMask[x] == '?')
continue;

// If the mask char is not a wildcard, ensure a match is made in the pattern.
if ((strMask[x] == 'x') && (btPattern[x] != this.m_vDumpedRegion[nOffset + x]))
return false;
}

// The loop was successful so we found the pattern.
return true;
}
#endregion

#region "sigScan Class Public Methods"
/// <summary>
/// FindPattern
///
/// Attempts to locate the given pattern inside the dumped memory region
/// compared against the given mask. If the pattern is found, the offset
/// is added to the located address and returned to the user.
/// </summary>
/// <param name="btPattern">Byte pattern to look for in the dumped region.</param>
/// <param name="strMask">The mask string to compare against.</param>
/// <param name="nOffset">The offset added to the result address.</param>
/// <returns>IntPtr - zero if not found, address if found.</returns>
public IntPtr FindPattern(byte[] btPattern, string strMask, int nOffset)
{
try
{
// Dump the memory region if we have not dumped it yet.
if (this.m_vDumpedRegion == null || this.m_vDumpedRegion.Length == 0)
{
if (!this.DumpMemory())
return IntPtr.Zero;
}

// Ensure the mask and pattern lengths match.
if (strMask.Length != btPattern.Length)
return IntPtr.Zero;

// Loop the region and look for the pattern.
for (int x = 0; x < this.m_vDumpedRegion.Length; x++)
{
if (this.MaskCheck(x, btPattern, strMask))
{
// The pattern was found, return it.
return new IntPtr((int)this.m_vAddress + (x + nOffset));
}
}

// Pattern was not found.
return IntPtr.Zero;
}
catch (Exception ex)
{
return IntPtr.Zero;
}
}

/// <summary>
/// ResetRegion
///
/// Resets the memory dump array to nothing to allow
/// the class to redump the memory.
/// </summary>
public void ResetRegion()
{
this.m_vDumpedRegion = null;
}
#endregion

#region "sigScan Class Properties"
public Process Process
{
get { return this.m_vProcess; }
set { this.m_vProcess = value; }
}
public IntPtr Address
{
get { return this.m_vAddress; }
set { this.m_vAddress = value; }
}
public Int32 Size
{
get { return this.m_vSize; }
set { this.m_vSize = value; }
}
#endregion

}
}

This uses the FindPattern method that is fairly commonly known, I just converted it to C#.

This doesn't wrap around VirtualQueryEx so the base + size is up to you to be sure is proper and accessible. This also dumps the memory once rather then per-each scan. If you need to rescan with a new dump each time just call ResetRegion() before scanning again.

This is from 2009 so you can write things a bit cleaner with Linq and such now.
_________________

- Retired.

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