CVE-2024-47406

Executive Summary

CVE-2024-47406 is a critical authentication bypass vulnerability affecting Sharp and Toshiba Tec Multifunction Printers (MFPs). The flaw resides in the improper processing of HTTP authentication requests, allowing an unauthenticated attacker to bypass security controls and gain unauthorized access to the device. With a CVSS score of 9.1, this vulnerability poses a severe risk to enterprise environments where these MFPs are deployed, potentially leading to data exfiltration, network compromise, and lateral movement. As of this report, no official patch has been released, and no public proof-of-concept (PoC) code is available.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby packages. It is a firmware-level issue in Sharp and Toshiba Tec MFPs.

CVSS Breakdown & Threat Level

• CVSS Score: 9.1 (Critical)
• Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: None
• User Interaction: None
• Scope: Unchanged
• Confidentiality Impact: High
• Integrity Impact: High
• Availability Impact: High

The threat level is critical due to the lack of required privileges, low attack complexity, and the potential for full device compromise.

Deep Dive & Mechanics

The vulnerability stems from improper handling of HTTP authentication requests within the MFP's web interface. Specifically, the device fails to validate authentication tokens or session cookies correctly, allowing an attacker to craft malicious HTTP requests that bypass the authentication mechanism. This can be exploited by sending specially crafted HTTP headers or manipulating the authentication flow to gain administrative access.

The affected components include the embedded web server and authentication modules. The flaw is likely due to insufficient input validation or flawed logic in the authentication state machine.

Vulnerable vs. Patched Code

Since no patch is available, a direct code comparison is not possible. However, based on the vulnerability description, the vulnerable code likely resembles:

# Vulnerable pseudo-code
def authenticate(request):
    if request.headers.get('Authorization') == 'Bearer admin':
        return True
    return False

A patched version would implement proper session management and token validation:

# Patched pseudo-code
def authenticate(request):
    token = request.headers.get('Authorization')
    if token and validate_token(token):
        return True
    return False

def validate_token(token):
    # Check token against secure database
    return token in valid_sessions

Exploitation & Lab Setup

Red Team

Lab Setup:

1. Deploy a vulnerable Sharp or Toshiba Tec MFP in an isolated network.
2. Use a tool like Burp Suite or custom Python scripts to interact with the device.

Exploitation Steps:

1. Identify the MFP's IP address and web interface port (typically 80 or 443).
2. Send a crafted HTTP request with manipulated authentication headers:

   GET /admin HTTP/1.1
   Host: 192.168.1.100
   Authorization: Bearer admin
   

3. If successful, the device will respond with administrative access.

Note: No public exploit code is available; this is a theoretical approach.

Blue Team

Detection:

• Monitor for unusual HTTP requests to MFP web interfaces, especially those with malformed or missing authentication headers.
• Look for repeated failed authentication attempts followed by sudden success.

Mitigation:

• Restrict network access to MFPs using firewall rules.
• Disable remote web management if not required.
• Implement network segmentation to isolate MFPs from critical systems.

Indicators of Compromise (IOCs)

• Network IOCs:

  • HTTP requests with Authorization: Bearer admin or similar tokens.
  • Unusual access to /admin or /config endpoints on MFP IPs.
  • Traffic from unknown IPs to MFP web interfaces.

• Host IOCs:

  • Unauthorized configuration changes on the MFP.
  • New user accounts or modified settings.
  • Log entries showing authentication bypass events.

Detection Engineering

YARA Rule

rule CVE_2024_47406_Sharp_Toshiba_MFP_AuthBypass {
    meta:
        description = "Detects HTTP requests attempting to exploit CVE-2024-47406"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2024-47406"
    strings:
        $auth_bypass = "Authorization: Bearer admin" nocase
        $admin_path = "/admin" nocase
    condition:
        $auth_bypass and $admin_path
}

Sigma Rule

title: CVE-2024-47406 Sharp/Toshiba MFP Authentication Bypass
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects HTTP requests with suspicious authentication headers targeting MFP web interfaces
author: Valters IT
date: 2025/04/10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'GET'
        cs-uri-stem: '/admin'
        cs-headers: 'Authorization: Bearer admin'
    condition: selection
falsepositives:
    - Legitimate administrative access
level: high

Suricata Rule

alert http any any -> $HOME_NET any (msg:"CVE-2024-47406 Sharp/Toshiba MFP Authentication Bypass"; flow:to_server; content:"Authorization"; nocase; content:"Bearer admin"; nocase; http_header; content:"/admin"; http_uri; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Isolate affected MFPs from the internet and untrusted networks.
2. Disable remote web management if not essential.
3. Implement strict firewall rules to allow only trusted IPs.

Long-term Fix:

• Await official firmware patches from Sharp and Toshiba Tec.
• Monitor vendor advisories for updates.
• Consider replacing vulnerable devices if patches are not released.

Workarounds:

• Use VPN or jump hosts for administrative access.
• Enable logging and monitoring for suspicious activity.

Valters IT