Shijia's 101 cracking experience

Dark family 101

It was not long for the younger brother to learn to crack. After being enlightened by the old four posts, he joined the learning and cracking queue. This post only review what you learned and make full use of it. It also allows you to make continuous progress in the future. Start cracking.
This is a small game called "submarine wars [Beidou edition]". Peid is used for Shell check. We can see that it is ASPack 2.12-> Alexey Solodovnikov. Open it with ollydbg. You can see "OK"
Click "no ".

We will go to the portal.


Based on the image instructions, we will push forward step by step.















Here, we have arrived at oep.



The next step is to remove the shell. Follow the image sequence step by step.







Click here and select any name. Use ollydbg to load the shell file we just removed. As you can see, we have not asked about anything, and we have reached the oep directly, which means the shelling is successful. Use peid to check the shell. You can see that
Borland Delphi 4.0-5.0




**************************************** **************************** ************************

I am interested in modifying the game. In the game, there is a kind of item that will enter the invincible time when it is eaten. Now, I am modifying it to make it invincible to eat any item. In the following figure, we find the invincible string in ollydbg.





We can see that the invincible string is found and double-click it.



We came to the invincible code segment.



We can see from the above that this is a switch statement. We can see that there must be a jump here. Here, we click the address 004946D5. We can see that there is a red arrow, and the source is the jump code.



That piece of code is based on the items you get and the capabilities you can get. We can use a jump to make it invincible. Change the code 004647C0 to JMP 004649D5.



Save the modification.



Select modify all



Any file name. After saving, run the file. We can know that any item we eat will be invincible. So far, the modification is successful.

**************************************** **************************** ************************

Of course, if you don't have any items, you will still die if you get a bomb. We might as well get an undead version.
Or the file after shelling. After importing the file, run the game and use the modifier to find the memory location for storing the lifecycle. Here is 00B14008. Return to ollydbg and press ctrl + G. Enter 00B14008.



Here we are





After the breakpoint is completed, continue the game and try to reduce your life. It will be interrupted. Here we will go.



Haha, here is the code for saving lives after the bullet. We changed it to an invincible state after the attack.



Save and run the game. Haha, in any case, we are not dead.

Tired! I typed so many words. This is what I learned during this period. It may be simple, but it is a motivation for me.
PS: which one can help me find the code that calculates the invincible time? I can't find it !!!