Writeup by Tian Cilliers of The Order of Bit (#1 South African CTF team!)
Chunk Norris is black belt in fast random number generation.
tiancilliers
tiancilliers
/ gctf_chunk_norris.md
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August 28, 2020 09:10
tiancilliers
/ gctf_sprint.md
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August 24, 2020 11:17
tiancilliers
/ inctf_findme.md
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August 2, 2020 14:35
We are provided an address and port. Running netcat on these tells us we need to find the number not matching (we have 3 attempts). We are then given a blob of base64 encoded data. Decoding this reveals a header of 78 9c, meaning this is zlib compressed data. Decompressing gives us data with a JPEG file header, and viewing this image results in the following:
[Insert Image Here]
tiancilliers
/ inctf_archride.md
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August 2, 2020 14:16
We are provided a file surprise which we notice, after running xxd -l 100 surprise, starts with the header 42 5a 68 39. This is recognizable as a BZip2 zipped file. After unzipping it, we are left with an x86-64 ELF file. We throw this into our decompiler of choice and find that it performs a few actions:
- Reads a 14-letter key
- Checks the XOR of various sets of 3 letters with some data embedded in the program
- If all this is satisfied, it overwrites the file
surprisewith a section of data in the program XORed with the key, repeating every 13 letters
tiancilliers
/ aotw_chal15.md
Last active
December 26, 2019 13:28
This challenge requires writing a program in the given language that prints out itself. This is commonly known as a quine.
Assemblium uses 2 stacks namely the data stack and code stack, with the following being executed when an instruction gets popped off the top of the code stack:
| Instruction | Result |
|---|