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THCTT24_running_number: init

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This commit is contained in:
minoplhy 2025-05-16 13:31:53 +07:00
parent cad68d475b
commit 180549d844
Signed by: minoplhy
GPG Key ID: 41D406044E2434BF
3 changed files with 77 additions and 0 deletions
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38
THCTT24_running_number/bruteforce.c Normal file
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#include <stdio.h>
#include <stdlib.h>
// This is da bruteforce code to get the right random seed
int main(void) {
int seed;
long sum;
int rand_var;
int i;
int md5_answer;
for (seed = 0; seed <= 1000000000;seed++) {
srand(seed);
sum = 0;
for (i = 0xa07; i > 0x7e7; i--) { // 2567 2023
if (i % 3 != 0) {
rand_var = rand();
sum = sum + rand_var;
}
}
printf("%u\n", seed);
if (sum == 0x5aad48bfa6) { // 389454282662
printf("THCTT24{");
for (i = 10; i < 0x4a; i++) { // 74
if ((i & 1) == 0) {
rand_var = rand();
md5_answer = rand_var % 0x10; // 16
printf("%x", md5_answer);
}
}
puts("}\n");
printf("Seed -> %d\n", seed);
break;
}
}
}

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THCTT24_running_number/original/running_number Executable file
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39
THCTT24_running_number/rewrite/running_number_rewrite.c Normal file
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#include <stdio.h>
#include <stdlib.h>
// This is rewrite of 'running_number' with help from ghidra
// while ensuring the integrity of program flows and so on
int main(void) {
int seed;
int rand_var;
int i;
int md5_answer;
printf("Time: ");
scanf("%u", &seed);
srand(seed);
long sum = 0;
for (i = 0xa07; i > 0x7e7; i--) { // 2567 2023
if (i % 3 != 0) {
rand_var = rand();
sum = sum + rand_var;
}
}
if (sum == 0x5aad48bfa6) { // 389454282662
printf("THCTT24{");
for (i = 10; i < 0x4a; i++) { // 74
if ((i & 1) == 0) {
rand_var = rand();
md5_answer = rand_var % 0x10;
printf("%x", md5_answer); // 16
}
}
puts("}");
} else {
puts("No Flag");
}
}