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GCCCTF 2024 I competed in GCCCTF last weekend. I played as an individual this week as many of us at Wolvsec have been busy preparing for our own upcoming CTF, WolvCTF 2024. I was able to solve a couple of the reversing challengs, warp-jump and rAnSoM, and placed 110th overall. The official challenge sources and writeups can be found here warp-jump Category: Rev Author: NineLine Points: 453 Solves: 20 Description A friend of yours simulated a Warp drive allowing faster-than-light travel, but the process if difficult and unpredictable.

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LACTF 2024 I was able to participate in LACTF this weekend with WolvSec and it was a lot of fun. We ended up placing 166th in the open division. These are my writeups for glottem, the-secret-of-java-island and aplet321 reversing challenges. The archived challenges are availible here. glottem Category: Rev Author: aplet123 Points: 455 Solves: 89 Description Haha glottem good! Note: The correct flag is 34 characters long. Files glottem: POSIX shell script, ASCII text executable, with very long lines

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Masked Squares Flag Checker Author: joseph Category: rev Difficulty: easy Points: 218 Solves: 62 Description This program checks the flag based on some simple arithmetic operations. Files ms_flag_checker - ms_flag_checker: ELF 64-bit LSB pie executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, BuildID[sha1]=a8e81b5edf26d75633d7f857771172e81689a563, for GNU/Linux 4.4.0, stripped Solve Begin by decompiling main with ghidra and cleaning up the code. undefined8 main(void) { long mask_ptr; byte *mask_info; int *sum_target_ptr; int masked_sum; int flag_ints [36]; char buf [40]; .

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All Fathers Wisdom Author: Pix Category: rev Difficulty: beginner Points: 100 Solves: 270 Description We found this binary in the backroom, its been marked as “The All Fathers Wisdom” - See hex for further details. Not sure if its just old and hex should be text, or they mean the literal hex. Anyway can you get this ‘wisdom’ out of the binary for us? Files the-all-fathers-wisdom - ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.

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Either or Neither nor Category: crypto Points: 100 Files chal.py - Python script, ASCII text executable Solve The contents of chal.py tell us that the flag has been xored with a key and we only have the resulting encrypted flag. #! /usr/bin/env python flag = "XXXXXXXXXXXXXXXXXXXXX" enc_flag = [91,241,101,166,85,192,87,188,110,164,99,152,98,252,34,152,117,164,99,162,107] key = [0, 0, 0, 0] KEY_LEN = 4 # Encrypt the flag for idx, c in enumerate(flag): enc_flag = ord(c) ^ key[idx % len(key)] The xor operation has properties that make it simple to reverse.

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