Start by putting the binary and the pdb file in the same folder and open the exe file in binary ninja. The find the CrackMe::validate_password function and relabeled symbols to get an understanding of what is happening. There are 5 checks done:

1. password length must be 12
2. first digit must be even
3. sum of the digits should be 69
4. the password must contain a substring from the variable pat, which is a substring of: YellowsGreenBlueRedOrangePurplesrc\\main.rs
5. last digit is odd

Here is the relabeled function in binary ninja:

For the 4th condition, it is possible to find exactly which substring from pat must be included in the password, but I didn’t check the function in detail because it seems like a lot of work. I assumed there is some kind of slicing being done. Knowing this information, I just bruteforced the 4th condition. Ignoring that condition for now, I crafted this string: 8XXXX7999999, which respects the other four conditions. Now, I just replaced XXXX with a different substring of YellowsGreenBlueRedOrangePurplesrc\\main.rs until 8eRed7999999 gave the flag.

Flag: csd{V41id_L1ceNs3_K3y}