I would definitely not recommend this way as it may crash the executable in the future in case it doesn't get loaded into its favored base address ( OptionalHeader.ImageBase) which is the default that all instructions needing relocation will use as a base to add an offset to. The first way to go about this is strip the relocation table from the PE.
BUSCAR UN ADDRES EN OLLYDBG PATCH
So there are a few ways to inject your code into another binary, I will address 2 here and I will also guess (after reading the comments) that you are trying to patch the binary that's on the disk.Ī. In short, this means that an executable running on an OS (in this example Windows) will not have the same base address across multiple executions. What you've encountered are the effects of ASLR. So when I call the MessageBoxA function, it errors out because I have loaded the wrong address for the Text and Caption arguments. Example is in pictures below:Īs you can see, I push the string onto the stack, but when I reload the modified program into the debugger again, the address of the string changes, but my code doesn’t. When I try to reference the ASCII string that I put in, the address is completely wrong. However, when I save the modified code to a new executable and run it with OllyDbg again, it doesn’t work. After that, I put a JMP instruction to the line of code after my JMP instruction that jumps to my injected code (yes, I just described a codecave or sort of). Then, I put the instruction that I replaced at the end of my injected code.
Next, I went to the first line of code in the program (simply by right clicking and pressing Go to Origin (or just press * on the number pad)) Then I replaced the first line with a JMP instruction to the address of the first PUSH 0 in my injected code. PUSH address_of_ASCII_string In this case, 00A6B668C Next, below that, I entered this asm code: PUSH 0 First, I opened up the exe in OllyDbg, then I went to the line that contains the ASCII text of “notepad.pdb.” Then I put an ASCII string below that (For example, “INJECTED NOTEPAD”). However, I ran into the problem of addresses.
BUSCAR UN ADDRES EN OLLYDBG WINDOWS 7
I was trying to inject some code (a little call to MessageBoxA) into the Windows 7 Notepad executable. You can find the virustotal hits of this sample here. You also notice that it is not using a commercial packer.This is my first post, and I am new to assembly and debugging, so bear with me please. We will be using a real malware that came from a spam. Follow in Dump - This allows to view the contents of a memory in Ollydbg's memory address view.CTRL+G - Go to an expression, e.g., specific address, address of API or addresses pointed by the registers.
We will be using these features for unpacking a malware sample. To start let us first look on the following useful Ollydbg features. In this blog, we will discuss a technique to unpack most malware using Ollydbg. They are sold and distributed usually underground. Unlike packers such as UPX, hacker-packer tools are not readily available. Today however, malware using a so called hacker-packer is proliferating. However, due to the fact that these are available tools, AV companies and reversers where able to study them and thus malwares packed with such third party packers can be easily unpacked these days. were being used by malware for years to somehow evade antivirus detection and make reversing difficult. Third party packers such as UPX, PECompact, Aspack, etc. For years, malware take advantage of packers to protect themselves against reverse analysis and AV detection.
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