IT Security Stack Exchange
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Questions tagged [assembly]

Assembly language is a low-level programming language whose instructions map almost 1-to-1 to a computer's machine code.

Assembly language is a low-level programming language whose instructions map almost 1-to-1 to a computer's machine code.

When analyzing an executable whose source code is unknown (e.g. the payload of an attack), the analyst can use a tool called a disassembler. A disassembler translates the machine code instructions (the numbers that form the unknown code) to assembly language, helping the analyst to better understand what the code is doing.

Below is a simple example of what assembly code looks like. Although assembly code looks quite cryptic, all the words are names or abbreviations. The example is for the x86 family of processors.

CLC
MOV  AX, 5   
ADD  AX, [SI]
MOV  [SI], AX
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Reverse engineering and buffer overflows: zero to hero

When I do CTFs, I can usually cope well with and understanding everything pretty much apart from buffer overflows, binary exploitation and reverse engineering Almost to the point that I would consider myself having zero knowledge at all. I grasp the…
pee2pee
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Can an attacker add malicious instructions to a cracked Password Manager app to exfiltrate credentials ? (1Password, oneSafe, etc.)

(In OSX) Would it be possible for an attacker to add into a password manager app (cracked illegal version, downloaded from a pirate website), instructions to make the program send credentials over the network? 1) When a cracker crack an app (OSX…
scugn1zz0
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Stack Protection off but still cant overwrite EIP

When Compiling with: gcc -m32 -fno-pie -no-pie -g bof.c -fno-stack-protector -z execstack -o bof32 I am able to overwrite the return address with just about any value except a valid return address. When I try to use a Valid return address the last…
zeroskilz
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Mov byte to addres inside a register

I am trying to write a shell insertion decoder (my encoder works as expected). But when I try to move one byte to the address inside a register i face a Segmentation fault. The error happens in this line: mov BYTE PTR [rdi],bl Here is my…
alacerda
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Do disassemblers detect standard functions?

Do disassemblers detect the use of C/C++ standard functions and specify them in the output code, adding the #include line to the appropriate header file (such as stdio.h or even windows.h)? If not, does the whole big library is being recognized as…
Reflection
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Trying to secure a code

I am trying to make hard to a code to be modified. Security is my concern. Ok, I know what you guys will say about piracy, bla bla bla. Lets refrain from that discussion. I am trying to collect ideas to do things differently in code. Things like…
Duck
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Reverse Engineer and Exploits researching

Can some one give me a start point for finding exploits in software and reverse engineering? I need some kind of a book or a site... I have background with programming with high and low level such as assembly... I want to know how the "hackers"…
Asaf fisher
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