C # Assembly generation 07, tampered with Assembly

The following aspects are used to differentiate different assemblies:
○ Assembly name: Name
○ Assembly version: Version
○ Assembly Public Key: Public token
○ Assembly culture: Culture

 

If you do not strictly follow these steps to create an assembly, the Assembly is easily tampered. This article describes how to tamper with the Assembly.

 

→ Clear all files in the as folder of drive F
→ Create the dog. CS class in the as folder, open it in notepad, write as follows, and save

using System;
public class Dog
{
    public static void MakeSound()
    {
Console. writeline ("Wang ");
    }
}

→ Compile dog. cs into an assembly

→ Decompile the dog. dll assembly and view the Il code

 

// Metadata version: v4.0.30319
.assembly extern mscorlib
{
  .publickeytoken = (B7 7A 5C 56 19 34 E0 89 )                         // .z\V.4..
  .ver 4:0:0:0
}
.assembly Dog
{
  .custom instance void [mscorlib]System.Runtime.CompilerServices.CompilationRelaxationsAttribute::.ctor(int32) = ( 01 00 08 00 00 00 00 00 ) 
  .custom instance void [mscorlib]System.Runtime.CompilerServices.RuntimeCompatibilityAttribute::.ctor() = ( 01 00 01 00 54 02 16 57 72 61 70 4E 6F 6E 45 78   // ....T..WrapNonEx
                                                                                                             63 65 70 74 69 6F 6E 54 68 72 6F 77 73 01 )       // ceptionThrows.
  .hash algorithm 0x00008004
  .ver 0:0:0:0
}
.module Dog.dll
// MVID: {A8BAEEAB-2DF4-425C-B851-87260378D735}
.imagebase 0x10000000
.file alignment 0x00000200
.stackreserve 0x00100000
.subsystem 0x0003       // WINDOWS_CUI
.corflags 0x00000001    //  ILONLY
// Image base: 0x00400000
// =============== CLASS MEMBERS DECLARATION ===================
.class public auto ansi beforefieldinit Dog
       extends [mscorlib]System.Object
{
  .method public hidebysig static void  MakeSound() cil managed
  {
// Code size 13 (0xd)
    .maxstack  8
    IL_0000:  nop
    IL_0001:  ldstr      bytearray (6A 6C 6A 6C 6A 6C )                               // jljljl
    IL_0006:  call       void [mscorlib]System.Console::WriteLine(string)
    IL_000b:  nop
    IL_000c:  ret
  } // end of method Dog::MakeSound
  .method public hidebysig specialname rtspecialname 
          instance void  .ctor() cil managed
  {
// Code size 7 (0x7)
    .maxstack  8
    IL_0000:  ldarg.0
    IL_0001:  call       instance void [mscorlib]System.Object::.ctor()
    IL_0006:  ret
  } // end of method Dog::.ctor
} // end of class Dog

○. Assembly dog indicates that the Assembly name is dog.
○. Ver 0: 0: 0: 0: 0 in the Assembly dog statement block indicates that the Assembly version has not been specially set.
○ The Assembly dog statement block does not contain public token or culture information.

→ Create the mainclass. CS class in the as folder, open it in notepad, write as follows, and save

using System;
class MainClass
{
    static void Main()
    {
        Dog.MakeSound();
    }
}

Compile and translate mainclass.cs, and use dog.dllto generate mainclass.exe.

→Mainclass.exe

→ If you want to tamper with dog. dll, delete dog. dll first.

→ Create the anotherdog. CS class in the as folder, open it in notepad, write as follows, and save

using System;
public class Dog
{
    public static void MakeSound()
    {
Console. writeline ("How is a puppy called ~ ");
    }
}

→ Compile the anotherdog. CS class and generate a dog. dll assembly.

Then run mainclass.exe.

The Assembly has been tampered.

 

Summary: When an assembly is generated, it is easy to tamper with the Assembly if no special settings are made for the assembly version, public key, and culture.

 

"C # Assembly series" includes:

C # Assembly series 01, use NotePad to write C # And il code, use the DOS command to compile the assembly, and run the C # Assembly series 02 program, use NotePad to view the Il code C # Assembly series 03 of the executable assembly, reference multiple Module C # Assembly series 04, when an Assembly contains multiple modules, you can understand the keyword internal C # Assembly generation 05, so that the Assembly contains multiple modules C # Assembly generation 06, assembly list, differences between EXE and dll c # Assembly series 07: tampered with Assembly

 

References:

Http://www.computersciencevideos.org/created by Jamie King

C # Assembly generation 07, tampered with Assembly