CVE-2023-47352

Executive Summary

CVE-2023-47352 identifies a critical security flaw in Technicolor TC8715D devices where default WPA2 security passwords are predictable. An attacker who scans for SSID and BSSID values can predict these passwords, leading to unauthorized network access. This vulnerability is particularly concerning due to the lack of a known patch, leaving many devices exposed. The predictable password generation mechanism allows for offline brute-force attacks or direct prediction, compromising the confidentiality and integrity of the network.

Supply Chain & Package Security

This vulnerability is not related to any software package ecosystem (NPM, PyPI, Go, Ruby). It is a hardware/firmware issue in the Technicolor TC8715D router.

CVSS Breakdown & Threat Level

The CVSS score is 0.0, indicating insufficient data for a standard score. However, based on the description, the vulnerability has the following characteristics:

• Attack Vector: Network (AV:N) – attacker can exploit remotely.
• Attack Complexity: Low (AC:L) – no special conditions required.
• Privileges Required: None (PR:N) – no authentication needed.
• User Interaction: None (UI:N) – no user action required.
• Scope: Unchanged (S:U) – exploitation does not affect other components.
• Confidentiality Impact: High (C:H) – attacker gains network access.
• Integrity Impact: High (I:H) – attacker can modify network traffic.
• Availability Impact: High (A:H) – attacker can disrupt network services.

Threat Level: Critical. The predictable password allows for immediate network compromise.

Deep Dive & Mechanics

The vulnerability stems from a flawed algorithm used to generate default WPA2 passwords on Technicolor TC8715D devices. The algorithm likely uses a combination of the SSID and BSSID (MAC address) in a deterministic way, making the password predictable. An attacker can:

1. Scan for SSIDs broadcast by Technicolor TC8715D devices.
2. Capture the BSSID (MAC address) of the device.
3. Use a known algorithm or brute-force to derive the default password.
4. Connect to the Wi-Fi network and gain full access.

This is a classic example of CWE-330: Use of Insufficiently Random Values. The password generation lacks entropy, making it susceptible to prediction.

Vulnerable vs. Patched Code

Since no patch is available, there is no patched code to compare. The vulnerable code is the firmware's password generation function. A hypothetical patched version would use a cryptographically secure random number generator (CSPRNG) to create unique, unpredictable passwords.

Vulnerable Code (Conceptual):

def generate_password(ssid, bssid):
    # Weak: uses deterministic hash of SSID and BSSID
    return hashlib.md5(ssid + bssid).hexdigest()[:8]

Patched Code (Conceptual):

import secrets
def generate_password():
    # Strong: uses CSPRNG
    return secrets.token_hex(8)

Exploitation & Lab Setup

Red Team

Objective: Predict and use the default WPA2 password to gain network access.

Tools Required:

• A wireless adapter supporting monitor mode (e.g., Alfa AWUS036ACH)
• Airodump-ng (part of aircrack-ng suite)
• Python script for password prediction

Steps:

1. Scan for Target: Use airodump-ng to find Technicolor TC8715D devices.

   sudo airodump-ng wlan0mon
   

2. Capture BSSID and SSID: Note the BSSID (MAC) and SSID of the target.
3. Predict Password: Run a Python script that implements the known algorithm.

   import hashlib
   ssid = "Technicolor-XXXX"
   bssid = "AA:BB:CC:DD:EE:FF"
   # Example algorithm (hypothetical)
   password = hashlib.md5(ssid.encode() + bssid.replace(":", "").encode()).hexdigest()[:8]
   print(f"Predicted password: {password}")
   

4. Connect: Use the predicted password to connect to the Wi-Fi network.

Blue Team

Objective: Detect and mitigate exploitation attempts.

Detection:

• Monitor for multiple failed authentication attempts from unknown MAC addresses.
• Use WPA2-Enterprise with 802.1X authentication instead of pre-shared keys.
• Implement a wireless intrusion detection system (WIDS) to detect brute-force attacks.

Mitigation:

• Change the default password immediately after device setup.
• Disable WPS if enabled, as it can be used to bypass WPA2.
• Apply firmware updates if available (none currently).

Indicators of Compromise (IOCs)

• Network Traffic: Unusual number of deauthentication packets or probe requests from unknown devices.
• Logs: Repeated WPA2 authentication failures in router logs.
• MAC Addresses: Unknown MAC addresses successfully connecting to the Wi-Fi network.
• SSID: Any SSID starting with "Technicolor-" is potentially vulnerable.

Detection Engineering

YARA Rule

rule Detect_Technicolor_Default_Password_Exploit {
    meta:
        description = "Detects attempts to exploit CVE-2023-47352 by scanning for Technicolor SSIDs"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2023-47352"
    strings:
        $ssid_pattern = /Technicolor-[A-F0-9]{4}/ nocase
        $bssid_pattern = /([0-9A-Fa-f]{2}[:-]){5}([0-9A-Fa-f]{2})/
    condition:
        $ssid_pattern or $bssid_pattern
}

Sigma Rule

title: Technicolor Default Password Prediction Attempt
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects network scans targeting Technicolor TC8715D devices for default password prediction
author: Valters IT
date: 2025-04-10
logsource:
    category: network_connection
    product: windows
detection:
    selection:
        EventID: 5156
        DestinationPort: 67
        SourcePort: 68
    condition: selection
falsepositives:
    - Legitimate network scans
level: high

Suricata Rule

alert udp any any -> any 67 (msg:"CVE-2023-47352 Technicolor Default Password Prediction"; content:"Technicolor-"; offset:0; depth:12; classtype:attempted-recon; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Change the default WPA2 password to a strong, random password.
2. Disable WPS (Wi-Fi Protected Setup) if enabled.
3. Monitor network logs for unauthorized access attempts.

Long-Term Solutions:

• Contact Technicolor for firmware updates (none available as of now).
• Consider replacing the device with a more secure alternative.
• Implement network segmentation to limit exposure of vulnerable devices.

Workarounds:

• Use MAC address filtering as an additional layer of security (not foolproof).
• Enable WPA3 if supported by the device (unlikely for this model).

Valters IT
Securing Digital Frontiers