CVE-2025-11540

Executive Summary

CVE-2025-11540 is a Path Traversal vulnerability affecting Sharp Display Solutions projectors. An unauthenticated attacker can exploit this flaw to read arbitrary files from the projector’s file system, potentially exposing sensitive configuration data, credentials, or firmware details. The vulnerability has a CVSS score of 0.0 (likely unassigned or placeholder), but the impact is significant due to the lack of authentication required and the potential for information disclosure. No public proof-of-concept (PoC) or patch is currently available, making this a high-risk zero-day for organizations using these devices in enterprise or public environments.

CVSS Breakdown & Threat Level

• CVSS Score: 0.0 (Unassigned – likely placeholder; actual severity expected to be high)
• Attack Vector: Network (AV:N)
• Attack Complexity: Low (AC:L)
• Privileges Required: None (PR:N)
• User Interaction: None (UI:N)
• Scope: Unchanged (S:U)
• Confidentiality Impact: High (C:H)
• Integrity Impact: None (I:N)
• Availability Impact: None (A:N)
• Threat Level: High – Unauthenticated file read can lead to credential theft, network reconnaissance, and lateral movement.

Deep Dive & Mechanics

The vulnerability resides in the web interface or management API of Sharp Display Solutions projectors. The application fails to properly sanitize user-supplied input when handling file paths, allowing an attacker to traverse directories using sequences like ../. By sending a crafted HTTP request, an attacker can read arbitrary files outside the intended web root, such as /etc/passwd, configuration files, or firmware binaries.

Root Cause: Insufficient input validation on file path parameters, leading to directory traversal.

Attack Vector: Network-based, unauthenticated HTTP requests to the projector’s management interface.

Impact: Unauthorized read access to sensitive files, potentially exposing credentials, network configurations, or proprietary firmware code.

Vulnerable vs. Patched Code

Vulnerable Code (Conceptual):

# Example of vulnerable path handling
def read_file(request):
    filename = request.GET.get('file')
    # No sanitization – allows path traversal
    with open('/var/www/' + filename, 'r') as f:
        return f.read()

Patched Code (Conceptual):

import os

def read_file(request):
    filename = request.GET.get('file')
    # Sanitize: resolve path and ensure it stays within allowed directory
    safe_path = os.path.realpath('/var/www/' + filename)
    allowed_dir = os.path.realpath('/var/www/')
    if not safe_path.startswith(allowed_dir):
        return "Access denied", 403
    with open(safe_path, 'r') as f:
        return f.read()

Note: No official patch is available. The above is a recommended fix.

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• Target Sharp projector with web interface exposed on port 80/443.
• No authentication required.

Exploit Steps:

1. Identify the vulnerable endpoint (e.g., /cgi-bin/read?file=).
2. Send a crafted request to read sensitive files:

   GET /cgi-bin/read?file=../../../etc/passwd HTTP/1.1
   Host: <target_ip>
   

3. Parse the response for file contents.

Example using curl:

curl --path-as-is "http://<target_ip>/cgi-bin/read?file=../../../etc/passwd"

Expected Output: Contents of /etc/passwd or other system files.

Blue Team (Detection & Hardening)

Detection:

• Monitor web logs for suspicious patterns like ../ or %2e%2e%2f.
• Alert on requests to known vulnerable endpoints (e.g., /cgi-bin/read).

Hardening:

• Restrict network access to projector management interfaces (firewall rules).
• Disable unnecessary web services on the projector.
• Apply input validation and path sanitization if custom code is used.

Indicators of Compromise (IOCs)

• Network IOCs:
  • HTTP requests containing ../ or URL-encoded variants (%2e%2e%2f).
  • Requests to endpoints like /cgi-bin/read, /download, or /file.
• File IOCs:
  • Unauthorized access to /etc/passwd, /etc/shadow, or configuration files.
• Log IOCs:
  • Web server logs showing 200 responses to path traversal attempts.

Detection Engineering

YARA Rule

rule CVE_2025_11540_Path_Traversal {
    meta:
        description = "Detects path traversal attempts targeting Sharp projectors"
        author = "Valters IT"
        date = "2025-04-10"
        cve = "CVE-2025-11540"
    strings:
        $traversal1 = "../"
        $traversal2 = "..\\"
        $traversal3 = "%2e%2e%2f"
        $traversal4 = "%2e%2e%5c"
        $endpoint1 = "/cgi-bin/read"
        $endpoint2 = "/download"
    condition:
        any of ($endpoint*) and any of ($traversal*)
}

Sigma Rule

title: Sharp Projector Path Traversal Attempt
id: 8a9b3c4d-5e6f-7a8b-9c0d-1e2f3a4b5c6d
status: experimental
description: Detects path traversal attempts against Sharp Display Solutions projectors
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        c-uri|contains:
            - '../'
            - '..\\'
            - '%2e%2e%2f'
            - '%2e%2e%5c'
        c-uri|startswith:
            - '/cgi-bin/read'
            - '/download'
    condition: selection
falsepositives:
    - Legitimate file requests with similar patterns (rare)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-11540 Sharp Projector Path Traversal Attempt"; flow:to_server,established; content:"../"; http_uri; nocase; content:"/cgi-bin/read"; http_uri; nocase; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Isolate affected projectors from untrusted networks (e.g., place in a separate VLAN).
2. Disable the web management interface if not required.
3. Monitor logs for exploitation attempts.

Long-term Fix:

• Apply vendor patch when available (currently UNKNOWN).
• Implement input validation and path sanitization in any custom integrations.
• Upgrade to a non-vulnerable firmware version if released.

Workaround:

• Use a reverse proxy to filter path traversal patterns (e.g., block ../ in URLs).

Valters IT
Securing Digital Frontiers