In computer security, a shellcode is a small piece of code used as the payload in the exploitation of a software vulnerability. It is called "shellcode" because it typically starts a command shell from which the attacker can control the compromised machine, but any piece of code that performs a ...

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5
votes
1answer
381 views

Stack canaries protection and ROP

As far as I know stack canaries are values written on the stack that, if overwritten by a buffer overflow, force the application to close at return. My question is: if I overwrite both EIP and stack ...
4
votes
2answers
1k views

Do I always have to overwrite EIP to get to write on the stack in a buffer overflow?

Do I always have to overwrite EIP to get to write on the stack in a buffer overflow? How's the memory organized? I can't find a proper graph with google
10
votes
2answers
5k views

How “leaking pointers” to bypass DEP/ASLR works

I was wondering if anyone could give me some clues on how "leaking pointers" to bypass DEP/ASLR work. I read here: The only way to reliably bypass DEP and ASLR is through an pointer leak. This ...
3
votes
1answer
2k views

Stack smashing keep getting segmentation fault

I have a homework assignment to do stack smashing, The exploit code creates a badfile in which the vulnerable file reads and buffer over flow occurs. I have already did the 2 commands below to ...
2
votes
1answer
326 views

How to achieve interactive shell attack?

Usually when a person gets a shell by attacking some vulnerabilities, what a person gets is non-interactive shell. So when I call FTP interactive client, shell fails. Is there any way I can do ...
3
votes
2answers
1k views

Shellcode that is smaller than 295 bytes that spawns a shell [closed]

Metasploit payloads produce more than 300-byte shellcodes. But I want my shell-spawning shellcodes to be less than 295 bytes. Can anyone show me the links to these shellcodes? Thanks.
6
votes
3answers
870 views

What methodologies are useful when reverse-engineering malware / shellcode?

Whilst I'm familiar with reverse engineering techniques from a technical standpoint, I've never found a good methodology for approaching and dissecting malware / shellcode. I've found hundreds of ...
2
votes
1answer
653 views

What tricks can be used to prevent debugging?

What tricks can be used to prevent or hinder debugging? Examples: IsDebuggerPresent API on Windows Exception handlers used for program flow. GetTickCount / rdtsc checks. Are there any good ...
4
votes
3answers
1k views

Are there any tools that focus on shellcode analysis?

Shellcode presents certain challenges for disassembly. It often self-modifies, jumps to the stack (where the shellcode will likely be placed), and relies on certain unusual tricks that standard ...
34
votes
2answers
15k views

How do ASLR and DEP work?

How do Address Space Layout Randomisation (ASLR) and Data Execution Prevention (DEP) work, in terms of preventing vulnerabilities from being exploited? Can they be bypassed?