Sting - ImaginaryCTF
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Description
Enter the beehive. Don't get stung.
Analysis
When opening the elf file in gdb, we can see that our input was being subtracted by constant 1 and then it was being compared with a string constant.
string constant: jdug|tus2oht`5s4ou`i2ee4o`28c32b7:~
So taking the string and subtracting with constant 1 gives us the flag.
Heres a quick snippet in C
.
decode.c
#include <stdio.h>
#include <string.h>
int main() {
char *string = "jdug|tus2oht`5s4ou`i2ee4o`28c32b7:~";
int n = strlen(string);
for (int i = 0; i < n; i++) {
printf("%c", string[i] - 1);
}
return 0;
}
flag:
ictf{str1ngs_4r3nt_h1dd3n_17b21a69}