CVE-2025-49164

Executive Summary

CVE-2025-49164 exposes a critical cryptographic weakness in Arris VIP1113 devices running KreaTV SDK. The firmware decryption key is hard-coded and publicly disclosed as cd1c2d78f2cba1f73ca7e697b4a485f49a8a7d0c8b0fdc9f51ced50f2530668a. This allows an attacker with physical or local network access to decrypt the firmware, extract sensitive data, reverse-engineer the device, or forge firmware updates. The vulnerability is classified as CWE-321 (Use of Hard-coded Cryptographic Key) with a CVSS v3.1 base score of 4.3 (Medium). No official patch or mitigation has been released by Arris. The EPSS score is 0.0%, indicating low exploitation likelihood in the wild, but the technical impact is significant for targeted attacks.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby packages. It affects embedded firmware in Arris VIP1113 hardware devices.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N
• Base Score: 4.3 (Medium)
• Attack Vector: Local (requires physical or local network access to the device)
• Attack Complexity: Low
• Privileges Required: High (attacker must already have some access to the device)
• User Interaction: None
• Scope: Unchanged
• Confidentiality Impact: High (firmware decryption exposes all stored data)
• Integrity Impact: None (key does not directly allow modification)
• Availability Impact: None

Threat Level: Medium. The key is publicly known, but exploitation requires local access. However, once decrypted, the firmware can be analyzed for further vulnerabilities.

Deep Dive & Mechanics

The Arris VIP1113 is a set-top box or similar embedded device using KreaTV SDK. The firmware is encrypted to protect intellectual property and prevent tampering. However, the decryption key is hard-coded in the device's bootloader or firmware update mechanism and has been publicly leaked. The key is a 256-bit hex string: cd1c2d78f2cba1f73ca7e697b4a485f49a8a7d0c8b0fdc9f51ced50f2530668a.

Mechanism:

1. The device boots and loads the encrypted firmware from flash memory.
2. The bootloader or a secure element uses the hard-coded key to decrypt the firmware in memory.
3. An attacker who obtains a firmware image (e.g., via a firmware update file or by dumping flash) can use the same key to decrypt it offline.
4. Decrypted firmware reveals the entire filesystem, including proprietary code, configuration files, credentials, and potentially other hard-coded secrets.

Impact:

• Reverse engineering of the device's software stack.
• Extraction of hard-coded credentials, API keys, or certificates.
• Identification of additional vulnerabilities (e.g., buffer overflows, command injection).
• Potential for forging firmware updates if the signing mechanism is also compromised.

Vulnerable vs. Patched Code

Vulnerable Code (Conceptual): The firmware decryption routine likely contains a hard-coded key similar to:

unsigned char key[32] = {
    0xcd, 0x1c, 0x2d, 0x78, 0xf2, 0xcb, 0xa1, 0xf7,
    0x3c, 0xa7, 0xe6, 0x97, 0xb4, 0xa4, 0x85, 0xf4,
    0x9a, 0x8a, 0x7d, 0x0c, 0x8b, 0x0f, 0xdc, 0x9f,
    0x51, 0xce, 0xd5, 0x0f, 0x25, 0x30, 0x66, 0x8a
};

Patched Code (Hypothetical): A secure implementation would derive the key from a hardware unique secret (e.g., eFuse, TPM) or use a public-key cryptography scheme where the private key is never stored in the device. Example:

// Use hardware security module (HSM) to derive key
if (!HSM_GetDerivedKey(&key, DEVICE_ID)) {
    // Handle error
}

No official patch exists. The vendor must redesign the firmware encryption mechanism.

Exploitation & Lab Setup

Red Team

Objective: Decrypt firmware to extract secrets and identify further vulnerabilities.

Prerequisites:

• Physical access to an Arris VIP1113 device or a firmware update file.
• A computer with Python and OpenSSL installed.

Steps:

1. Obtain a firmware image (e.g., via dd from flash or from a vendor update).
2. Use the known key to decrypt the firmware. Assuming AES-256-CBC (common for embedded firmware):

   openssl enc -d -aes-256-cbc -K cd1c2d78f2cba1f73ca7e697b4a485f49a8a7d0c8b0fdc9f51ced50f2530668a -iv 00000000000000000000000000000000 -in firmware.bin -out firmware_decrypted.bin
   

   (Note: IV may vary; try zero or extract from firmware header.)
3. Analyze the decrypted firmware using binwalk, strings, and a hex editor.
4. Extract file system (e.g., SquashFS) and search for credentials, API keys, or other hard-coded secrets.

Python Script Example:

from Crypto.Cipher import AES
import sys

key = bytes.fromhex("cd1c2d78f2cba1f73ca7e697b4a485f49a8a7d0c8b0fdc9f51ced50f2530668a")
iv = b'\x00' * 16  # Adjust if needed

with open(sys.argv[1], 'rb') as f:
    ciphertext = f.read()

cipher = AES.new(key, AES.MODE_CBC, iv)
plaintext = cipher.decrypt(ciphertext)

with open('decrypted_firmware.bin', 'wb') as f:
    f.write(plaintext)

Blue Team

Detection:

• Monitor for unauthorized physical access to devices.
• Log and alert on any attempts to dump firmware (e.g., via JTAG, UART, or flash reading).
• Use network monitoring to detect unusual firmware update requests or large data exfiltration from the device.

Hunting:

• Search for the known key in network traffic or logs (e.g., if an attacker tries to exfiltrate it).
• Check for decrypted firmware images on internal file shares.

Mitigation:

• Isolate Arris VIP1113 devices on a separate VLAN with strict access controls.
• Disable unused physical interfaces (e.g., USB, UART) if possible.
• Monitor for firmware update anomalies (e.g., unsigned updates).
• Contact Arris for a firmware update that removes the hard-coded key.

Indicators of Compromise (IOCs)

• Firmware Hash (SHA256): cd1c2d78f2cba1f73ca7e697b4a485f49a8a7d0c8b0fdc9f51ced50f2530668a (the key itself, but also any firmware image that uses this key)
• Decrypted Firmware Artifacts: Files containing strings like KreaTV, Arris, or specific model numbers.
• Network Traffic: Unusual outbound connections from the device to unknown IPs (potential data exfiltration).
• Physical Indicators: Tamper-evident seals broken, opened device casing.

Detection Engineering

YARA Rule

rule CVE_2025_49164_Arris_Firmware_Key {
    meta:
        description = "Detects the hard-coded firmware decryption key in Arris VIP1113 firmware"
        author = "Valters IT"
        date = "2025-05-30"
        reference = "CVE-2025-49164"
    strings:
        $key = { cd 1c 2d 78 f2 cb a1 f7 3c a7 e6 97 b4 a4 85 f4 9a 8a 7d 0c 8b 0f dc 9f 51 ce d5 0f 25 30 66 8a }
    condition:
        $key
}

Sigma Rule

title: Arris VIP1113 Hard-coded Firmware Key Detected
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects the presence of the known hard-coded firmware decryption key in files or memory
author: Valters IT
date: 2025-05-30
logsource:
    category: file_event
    product: windows
detection:
    selection:
        TargetFilename|contains: 'firmware.bin'
        TargetFilename|endswith: '.bin'
    condition: selection
falsepositives:
    - Legitimate firmware analysis by authorized personnel
level: high

Suricata Rule

alert tcp $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2025-49164 Arris VIP1113 Firmware Key Exfiltration"; content:"cd1c2d78f2cba1f73ca7e697b4a485f49a8a7d0c8b0fdc9f51ced50f2530668a"; nocase; classtype:attempted-recon; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Isolate Devices: Place Arris VIP1113 devices on a separate, restricted VLAN with no direct internet access.
2. Disable Unused Services: Turn off any debug interfaces (e.g., SSH, Telnet, UART) if possible.
3. Monitor Firmware Updates: Only accept signed firmware updates from the vendor. Verify signatures before applying.
4. Physical Security: Ensure devices are in locked environments to prevent physical tampering.

Long-term Fix:

• Vendor Action: Arris must release a firmware update that replaces the hard-coded key with a device-unique key derived from hardware secrets (e.g., eFuse, TPM) or uses public-key cryptography for firmware encryption.
• Replace Devices: If no patch is forthcoming, consider replacing the devices with models that have secure boot and encrypted firmware.

Workarounds:

• Implement network segmentation and strict access controls.
• Use a hardware security module (HSM) to manage keys if the device supports external key injection.

Valters IT
Securing Digital Frontiers