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Miz - InCTF Internationals 2021

AmunRha
Freakston
2021-08-19
Reversing / Linux

tl;dr

  • This is a fairly simple Maze challenge
  • Challenge is written in rust
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InCTFi Linux Reversing Maze Rust

2k - redpwnctf 2021

AmunRha
2021-07-22
Reversing / Linux

tl;dr

  • This is a simple stack based VM
  • 25-27 opcodes and 8 different constraints
  • Extract the constraints
  • Use z3 to find a satisfying model
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Linux VM Reversing

dummyper - AeroCTF 2021

fug1t1v3
2021-02-28
Reversing / Linux

tl;dr

  • The dump has some encrypted functions
  • The encrypted bytes are being xorred with a 32 byte key
  • Find the xor_key in the dump
  • Use xor_key offset to find the offset of AES_key and iv
  • AES_CBC decrypt to find flag
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Linux Reversing AES_CBC AeroCTF

Signal VM de1ta (Part 2) - de1CTF 2019

R3x
2019-08-09
Reversing / Linux

tl;dr

  • Challenge is a VM implemented over signals and ptrace
  • Reverse Instruction types and implementation
  • Use gdb scripting to find the executed code and get the pseudo VM code
  • Find out the algorithm (Max triangle sum) from VM instructions
  • Find an more optimized way to solve the problem (Or lazy solve it!).
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Linux VM Reversing Automation

Signal VM (Part 1) - de1CTF 2019

R3x
2019-08-08
Reversing / Linux

tl;dr

  • Challenge is a VM implemented over signals and ptrace
  • Reverse Instruction types and implementation
  • Use gdb scripting to find the executed code and get the pseudo VM code
  • Reverse the VM functionality (Hill cipher) for flag and profit
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Linux VM Reversing Automation

Copychall - Acebear CTF 2019

R3x
2019-04-25
Reversing / Linux

tl;dr

  • You need to pass 999 levels to get the flag.
  • Each of the levels involves multiple checks on input characters.
  • Each check happens in seperate functions which are decrypted during runtime.
  • Extract function order and arguments.
  • Automate finding input for each check.
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Linux Reversing

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  Projects
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    (Unraveling)
  •   bi0s-wiki
    (Free Encyclopedia)
  •   InCTF
    (Nationals CTF)
  •   InCTFj
    (Juniors CTF)

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