CVE-2025-8915

Executive Summary

CVE-2025-8915 exposes a critical security flaw in Kiloview N30 firmware version 2.02.246, where a hardcoded TLS private key and certificate are embedded in the firmware image. This allows any malicious adversary who extracts the firmware to perform a Man-in-the-Middle (MitM) attack against network traffic, decrypting and potentially modifying communications between the device and its management infrastructure. The vulnerability is unpatched, and no official fix has been released by Kiloview as of this report.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby packages. It is a firmware-level issue in an embedded device (Kiloview N30 video encoder/decoder). The hardcoded cryptographic material is part of the device’s binary firmware, making it a supply chain risk for any organization deploying these devices.

CVSS Breakdown & Threat Level

While no official CVSS vector is provided, based on the nature of the vulnerability (hardcoded cryptographic key in firmware, network-accessible MitM), a reasonable assessment is:

• Attack Vector (AV): Network (N) – The attacker can exploit this remotely.
• Attack Complexity (AC): Low (L) – Extracting the key from firmware is straightforward with basic reverse engineering tools.
• Privileges Required (PR): None (N) – No authentication needed to perform MitM.
• User Interaction (UI): None (N) – No user action required.
• Scope (S): Changed (C) – The attack impacts resources beyond the vulnerable component (e.g., backend servers).
• Confidentiality (C): High (H) – All encrypted traffic can be decrypted.
• Integrity (I): High (H) – Traffic can be modified.
• Availability (A): Low (L) – Denial of service possible by dropping or altering traffic.

Estimated CVSS Score: 9.8 (Critical)

Threat Level: Critical – Immediate action required to isolate or replace affected devices.

Deep Dive & Mechanics

The Kiloview N30 firmware (version 2.02.246) contains a hardcoded TLS private key and certificate. This means:

1. Firmware Extraction: An attacker can download the firmware from Kiloview’s website or extract it from a device via physical access or a previous compromise.
2. Key Extraction: Using tools like binwalk, firmware-mod-kit, or simple hex editors, the attacker locates the PEM-encoded private key and certificate within the firmware binary.
3. MitM Setup: The attacker positions themselves on the network path between the N30 device and its management server (e.g., for video streaming or configuration). They use the extracted private key to decrypt TLS sessions, impersonate the server, and intercept or modify traffic.
4. Impact: This allows the attacker to steal video feeds, alter device configurations, inject malicious commands, or pivot to other network resources.

The vulnerability is classified under CWE-321: Use of Hard-coded Cryptographic Key. The key is identical across all devices running this firmware version, making it a single point of failure.

Vulnerable vs. Patched Code

Vulnerable Code (Firmware 2.02.246): The firmware includes a file (e.g., server.key and server.crt) with hardcoded values. Example snippet (simulated):

-----BEGIN RSA PRIVATE KEY-----
MIIEpAIBAAKCAQEA...
-----END RSA PRIVATE KEY-----
-----BEGIN CERTIFICATE-----
MIIDXTCCAkWgAwIBAgIJ...
-----END CERTIFICATE-----

Patched Code (Not Available): A proper fix would involve:

• Removing the hardcoded key from firmware.
• Generating a unique key pair on first boot.
• Using a secure key storage mechanism (e.g., TPM or secure element).
• Implementing certificate pinning or mutual TLS.

Since no patch exists, the vulnerable code remains in production.

Exploitation & Lab Setup

Red Team (Offensive)

Lab Setup:

1. Obtain Kiloview N30 firmware version 2.02.246.
2. Extract the firmware using binwalk:

   binwalk -e firmware.bin
   

3. Locate the private key and certificate (e.g., in a .pem file or embedded in a binary).
4. Set up a MitM proxy (e.g., mitmproxy) with the extracted key:

   mitmproxy --listen-port 8443 --cert server.crt --key server.key
   

5. Redirect traffic from the N30 device to the proxy using ARP spoofing or DNS poisoning.
6. Decrypt and inspect all TLS traffic.

Exploit Code (Conceptual): No public exploit code exists, but the following Python script demonstrates key extraction:

import re

with open('firmware.bin', 'rb') as f:
    data = f.read()

# Find PEM-encoded private key
key_match = re.search(b'-----BEGIN RSA PRIVATE KEY-----(.*?)-----END RSA PRIVATE KEY-----', data, re.DOTALL)
if key_match:
    with open('extracted_key.pem', 'wb') as kf:
        kf.write(key_match.group())
    print("Private key extracted.")

Blue Team (Defensive)

Detection:

• Monitor for unexpected TLS certificates on the network.
• Use network anomaly detection for unusual traffic patterns (e.g., sudden increase in encrypted traffic to unknown IPs).
• Check for ARP spoofing or DNS poisoning indicators.

Mitigation:

• Isolate Kiloview N30 devices on a separate VLAN with strict firewall rules.
• Disable TLS if not required, or use a VPN tunnel for management traffic.
• Monitor firmware updates from Kiloview and apply immediately when available.
• Consider replacing the device with a secure alternative.

Indicators of Compromise (IOCs)

• Firmware Hash: SHA256 of firmware 2.02.246 (example: a1b2c3d4e5f6...)
• Hardcoded Certificate Serial: (e.g., 00:AB:CD:...)
• Network Traffic: TLS connections using the hardcoded certificate (detectable via JA3 fingerprinting).
• Processes: Unusual mitmproxy or sslstrip processes on network hosts.
• Files: Presence of server.key or server.crt in unexpected locations.

Detection Engineering

YARA Rule

rule CVE_2025_8915_Hardcoded_TLS_Key
{
    meta:
        description = "Detects hardcoded TLS private key in Kiloview N30 firmware"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-8915"
    strings:
        $key_header = "-----BEGIN RSA PRIVATE KEY-----"
        $cert_header = "-----BEGIN CERTIFICATE-----"
        $kiloview_str = "Kiloview" nocase
    condition:
        $key_header and $cert_header and $kiloview_str
}

Sigma Rule

title: Detection of Hardcoded TLS Key in Kiloview N30 Firmware
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects network traffic using the hardcoded TLS certificate from CVE-2025-8915
author: Valters IT
logsource:
    category: network_connection
    product: zeek
detection:
    selection:
        ja3_hash: "a1b2c3d4e5f6a7b8c9d0e1f2a3b4c5d6"  # Example JA3 hash of the hardcoded cert
    condition: selection
falsepositives:
    - Legitimate use of the same certificate (unlikely)
level: critical

Suricata Rule

alert tls any any -> any any (msg:"CVE-2025-8915 - Hardcoded TLS Certificate Detected"; tls.cert_serial:"00:AB:CD:12:34:56:78:90"; sid:1000001; rev:1;)

Remediation & Mitigation

1. Immediate: Isolate all Kiloview N30 devices from untrusted networks. Use a dedicated VLAN with strict ACLs.
2. Short-term: If possible, disable TLS on the device and use a VPN tunnel for management.
3. Long-term: Replace the device with a vendor that provides secure firmware with unique keys per device.
4. Monitoring: Deploy the YARA, Sigma, and Suricata rules above to detect exploitation attempts.
5. Vendor Communication: Contact Kiloview for a firmware update. If none is available, consider legal or regulatory reporting.

Valters IT
Securing Digital Frontiers