C # Assembly generation 07, tampered with assembly,

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

In C language-> what?

-> Is a whole. It is used to point to a struct, class in C ++, and other pointers containing sub-data to obtain sub-data. In other words, if we define a struct in C and declare a pointer pointing to this struct, we need to use "->" to retrieve the data in the struct using the pointer ".
For example:
Struct Data
{
Int a, B, c;
};/* Define struct */
Struct Data * p;/* define struct pointer */
Struct Data A = {1, 2, 3};/* declare variable */
Int x;/* declare a variable x */
P = & A;/* point p to */
X = p-> a;/* indicates that the data item a in the struct pointed to by p is assigned to x */
/* Because p points to A, p-> a = A. a, that is, 1 */

For the first problem, p = p-> next; this should appear in the linked list of C language. next here should be a struct pointer of the same type as p, and its definition format should be:
Struct Data
{
Int;
Struct Data * next;
};/* Define struct */
............
Main ()
{
Struct Data * p;/* declare the pointer Variable p */
......
P = p-> next;/* assign the value in next to p */
}
The linked list pointer is a difficulty in C language, but it is also the key. It is very useful to learn it. To be careful, you must first talk about variables and pointers.
What is a variable? The so-called variables should not be simply thought that the amount will become a variable. Let's use the question of our Dean: "Is the classroom changing ?" Change, because there are different people in the classroom every day, but they do not change, because the classroom is always there, and it does not become larger or smaller. This is the variable: There is a constant address and a variable storage space. Under normal circumstances, we only see the variable in the room, that is, its content, but do not pay attention to the variable address, but the C language pointer is the address of the room. We declare that variables are equivalent to building a house to store things. We can directly watch things in the house, while declaring pointers is equivalent to getting a positioner. When a pointer points to a variable, it is to use the pointer to locate the variable. Then we can use the pointer to find the variable "tracked" and get the content in it.
What about struct? The structure is equivalent to a villa composed of several houses, and several houses are bound for use together. Suppose there are many such villas distributed in a big maze, and each villa has a house. The location information of another villa is put in it. Now you have found the first villa with the positioner and obtained what you want from it (the data part of the linked list ), then, calculate the location of the next villa into your positioner (p = p-> next), and go down to the next villa ...... If you go on like this, you will know that the information of a villa on the ground is gone (p-> next = NULL), and your trip is over. This is the process of traversing a linked list. Now you can understand the meaning of p = p-> next!
Write so much. I hope you can understand.
If you want to learn c and C ++ well, you must be familiar with linked lists and pointers!

In C language-> what?

-> Is a whole. It is used to point to a struct, class in C ++, and other pointers containing sub-data to obtain sub-data. In other words, if we define a struct in C and declare a pointer pointing to this struct, we need to use "->" to retrieve the data in the struct using the pointer ".
For example:
Struct Data
{
Int a, B, c;
};/* Define struct */
Struct Data * p;/* define struct pointer */
Struct Data A = {1, 2, 3};/* declare variable */
Int x;/* declare a variable x */
P = & A;/* point p to */
X = p-> a;/* indicates that the data item a in the struct pointed to by p is assigned to x */
/* Because p points to A, p-> a = A. a, that is, 1 */

For the first problem, p = p-> next; this should appear in the linked list of C language. next here should be a struct pointer of the same type as p, and its definition format should be:
Struct Data
{
Int;
Struct Data * next;
};/* Define struct */
............
Main ()
{
Struct Data * p;/* declare the pointer Variable p */
......
P = p-> next;/* assign the value in next to p */
}
The linked list pointer is a difficulty in C language, but it is also the key. It is very useful to learn it. To be careful, you must first talk about variables and pointers.
What is a variable? The so-called variables should not be simply thought that the amount will become a variable. Let's use the question of our Dean: "Is the classroom changing ?" Change, because there are different people in the classroom every day, but they do not change, because the classroom is always there, and it does not become larger or smaller. This is the variable: There is a constant address and a variable storage space. Under normal circumstances, we only see the variable in the room, that is, its content, but do not pay attention to the variable address, but the C language pointer is the address of the room. We declare that variables are equivalent to building a house to store things. We can directly watch things in the house, while declaring pointers is equivalent to getting a positioner. When a pointer points to a variable, it is to use the pointer to locate the variable. Then we can use the pointer to find the variable "tracked" and get the content in it.
What about struct? The structure is equivalent to a villa composed of several houses, and several houses are bound for use together. Suppose there are many such villas distributed in a big maze, and each villa has a house. The location information of another villa is put in it. Now you have found the first villa with the positioner and obtained what you want from it (the data part of the linked list ), then, calculate the location of the next villa into your positioner (p = p-> next), and go down to the next villa ...... If you go on like this, you will know that the information of a villa on the ground is gone (p-> next = NULL), and your trip is over. This is the process of traversing a linked list. Now you can understand the meaning of p = p-> next!
Write so much. I hope you can understand.
If you want to learn c and C ++ well, you must be familiar with linked lists and pointers!