Nmap Output:

 

 

Dirb scan turned up nothing.

 

Let's view the web page.

 

 

Each door opens to another page.

 

and the source code is as follows.

 

 

Let's ask any hash to hash-identifier.

 

 

When we solve all the hashes with MD5, we see that the numbers are in order from 1 to 13.

 

In fact, it is enough to crack only 2 hashes for idor.

 

Numbers like -1,0,1 are typically unique when referring to the IDOR vulnerability because admin or test accounts are frequently present at these endpoints. Just try to visit those endpoints by obtaining the MD5 hash of these individual integers(https:///md5-string-of- [-1,0,1]) and we will get our flag.