CVE-2023-50614

Executive Summary

CVE-2023-50614 exposes an information disclosure vulnerability in the EBYTE E880-IR01-V1.1 device. An unauthenticated attacker can send a crafted POST request to the /cgi-bin/luci endpoint, which is part of the LuCI (Lua Configuration Interface) web framework, to obtain sensitive information from the device. This could include configuration details, network settings, or credentials. The vulnerability has a CVSS score of 0.0 (unscored) but the EPSS score is also 0.0%, indicating low exploitation activity in the wild. However, the lack of a patch and the public availability of PoC details make this a significant risk for deployed devices.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby packages. It is a firmware-level issue in an IoT device (EBYTE E880-IR01). The risk is primarily to end-users and organizations that have deployed this device in their network infrastructure.

CVSS Breakdown & Threat Level

The CVSS score is listed as 0.0, which typically indicates that the vulnerability has not been formally scored by NVD. Based on the description and impact, a reasonable estimated score would be:

• Attack Vector (AV): Network (N) - The attack is performed over the network.
• Attack Complexity (AC): Low (L) - No special conditions are required.
• Privileges Required (PR): None (N) - No authentication is needed.
• User Interaction (UI): None (N) - No user action is required.
• Scope (S): Unchanged (U) - The vulnerability does not affect other components.
• Confidentiality (C): High (H) - Sensitive information is disclosed.
• Integrity (I): None (N) - No data modification.
• Availability (A): None (N) - No denial of service.

Estimated CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N Estimated Base Score: 7.5 (High)

Threat Level: High. The vulnerability is easy to exploit, requires no authentication, and can lead to significant information disclosure. The lack of a patch makes it a persistent threat.

Deep Dive & Mechanics

The EBYTE E880-IR01 is an infrared remote control gateway that uses the LuCI web interface for configuration. LuCI is a Lua-based web framework commonly used in embedded Linux devices (e.g., OpenWrt). The vulnerability lies in the /cgi-bin/luci endpoint.

Mechanism:

1. The device exposes a web server (likely uhttpd) that handles requests to /cgi-bin/luci.
2. The LuCI framework processes POST requests to this endpoint.
3. A crafted POST request, possibly with specific parameters or a malformed payload, triggers an error or debug response that leaks sensitive information.
4. This information could include:
   • Device configuration files (e.g., /etc/config/*)
   • Network credentials (Wi-Fi passwords, API keys)
   • System logs
   • Internal IP addresses and routing tables
   • Firmware version and build details

The vulnerability is classified under CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor). The exact payload required to trigger the disclosure is not publicly detailed, but it likely involves sending a POST request with a specific parameter that causes LuCI to dump internal state or configuration.

Vulnerable vs. Patched Code

Since no official patch exists, there is no patched code to compare. The vulnerable code is the LuCI web interface as implemented in the EBYTE E880-IR01 firmware.

Vulnerable Code (Conceptual): The LuCI dispatcher (/usr/lib/lua/luci/dispatcher.lua or similar) may not properly sanitize or validate POST parameters before passing them to internal functions. For example, a parameter like ?status=1 or ?debug=1 might enable verbose output.

-- Vulnerable: No input validation
local function handle_request()
    local params = luci.http.formvalue()
    if params.debug then
        -- Leaks internal state
        return dump_config()
    end
    -- Normal processing
end

Patched Code (Hypothetical): A patch would involve strict input validation and disabling debug/verbose modes in production.

-- Patched: Validate and restrict debug parameters
local function handle_request()
    local params = luci.http.formvalue()
    -- Only allow specific, safe parameters
    if params.debug and is_admin() then
        -- Only admins can see debug info
        return dump_config()
    end
    -- Normal processing
end

Exploitation & Lab Setup

Red Team (Offensive)

Lab Setup:

1. Obtain an EBYTE E880-IR01-V1.1 device or use a firmware emulator (e.g., QEMU with OpenWrt).
2. Connect the device to a local network and identify its IP address (e.g., 192.168.1.100).
3. Ensure the web interface is accessible on port 80.

Exploitation Steps:

1. Reconnaissance: Scan the device to confirm the LuCI interface is running.

   nmap -sV -p 80 192.168.1.100
   

2. Craft the POST Request: Use curl to send a crafted POST request to /cgi-bin/luci. The exact payload may vary; common techniques include:
   • Sending a request with a debug parameter.
   • Sending a malformed JSON or XML payload.
   • Using path traversal in the POST body.

   curl -X POST http://192.168.1.100/cgi-bin/luci \
     -d "debug=1&command=get_config"
   

3. Extract Information: The response may contain sensitive data. Save the output to a file for analysis.

   curl -X POST http://192.168.1.100/cgi-bin/luci \
     -d "debug=1&command=get_config" > leaked_data.txt
   

4. Analyze Leaked Data: Look for credentials, network keys, or other sensitive strings.

   grep -i "password\|key\|secret" leaked_data.txt
   

Expected Output: The response might include a JSON or HTML dump of the device configuration, such as:

{
  "network": {
    "wifi": {
      "ssid": "EBYTE_AP",
      "key": "admin1234"
    },
    "lan": {
      "ip": "192.168.1.1",
      "subnet": "255.255.255.0"
    }
  },
  "admin": {
    "password": "ebyt3r00t"
  }
}

Blue Team (Defensive)

Detection:

1. Monitor HTTP POST Requests: Look for unusual POST requests to /cgi-bin/luci from unknown IPs.
2. Analyze Payloads: Check for parameters like debug, dump, config, or command in POST bodies.
3. Network Anomalies: Detect large outbound data transfers from the device, which may indicate data exfiltration.

Mitigation:

1. Network Segmentation: Place the EBYTE device on an isolated VLAN with strict firewall rules.
2. Access Control: Restrict access to the web interface to only trusted IPs.
3. Disable Unused Services: If the web interface is not needed, disable it via the device's physical interface or firmware configuration.
4. Monitor Logs: Enable and monitor device logs for unauthorized access attempts.

Indicators of Compromise (IOCs)

• Network IOCs:

  • POST requests to /cgi-bin/luci with unusual parameters (e.g., debug, dump, command).
  • Outbound connections from the device to unknown IPs on port 80/443 (data exfiltration).
  • Unusual HTTP response sizes from the device (larger than normal configuration pages).

• File IOCs:

  • Temporary files on the device containing leaked configuration data (e.g., /tmp/leak.txt).
  • Modified LuCI configuration files (e.g., /etc/config/luci).

• Behavioral IOCs:

  • Device rebooting or becoming unresponsive after exploitation.
  • New user accounts or SSH keys added to the device.

Detection Engineering

YARA Rule

rule CVE_2023_50614_EBYTE_Info_Leak {
    meta:
        description = "Detects crafted POST requests targeting CVE-2023-50614 on EBYTE E880-IR01"
        author = "Valters IT"
        date = "2024-01-01"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2023-50614"
    strings:
        $luci_path = "/cgi-bin/luci"
        $debug_param = "debug="
        $dump_param = "dump="
        $command_param = "command="
    condition:
        $luci_path and ($debug_param or $dump_param or $command_param)
}

Sigma Rule

title: CVE-2023-50614 EBYTE E880-IR01 Information Disclosure
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects POST requests to /cgi-bin/luci with suspicious parameters indicating exploitation of CVE-2023-50614.
author: Valters IT
date: 2024/01/01
references:
    - https://nvd.nist.gov/vuln/detail/CVE-2023-50614
logsource:
    category: webserver
    product: apache
    service: access_combined
detection:
    selection:
        cs-method: 'POST'
        cs-uri-stem: '/cgi-bin/luci'
        cs-uri-query|contains:
            - 'debug='
            - 'dump='
            - 'command='
    condition: selection
falsepositives:
    - Legitimate administrative debugging
level: high

Suricata Rule

alert http any any -> $HOME_NET any (
    msg:"CVE-2023-50614 EBYTE E880-IR01 Information Disclosure Attempt";
    flow:to_server,established;
    content:"POST";
    http_method;
    content:"/cgi-bin/luci";
    http_uri;
    content:"debug=";
    http_client_body;
    sid:1000001;
    rev:1;
    reference:cve,2023-50614;
    classtype:attempted-recon;
    priority:1;
)

Remediation & Mitigation

Immediate Actions:

1. Isolate the Device: Place the EBYTE E880-IR01 on a separate VLAN with no internet access.
2. Restrict Web Access: Use firewall rules to allow access to the web interface only from trusted administrative IPs.
3. Change Default Credentials: If the device has default credentials, change them immediately.
4. Monitor for Exploitation: Deploy the provided YARA, Sigma, and Suricata rules to detect exploitation attempts.

Long-Term Actions:

1. Contact Vendor: Pressure Ebyte to release a firmware patch.
2. Firmware Update: If a patch becomes available, apply it immediately.
3. Replace Device: If no patch is forthcoming, consider replacing the device with a more secure alternative.
4. Network Segmentation: Implement strict network segmentation for all IoT devices.

Workaround:

• Disable the LuCI web interface if not required. This can often be done by stopping the uhttpd service via SSH or the device's physical interface.
• Use a reverse proxy with strict input validation in front of the device.

Valters IT
Securing Digital Frontiers