Overview

A critical vulnerability has been discovered in Totolink N200RE 9.3.5u.6139_B20201216, a widely used networking device. The vulnerability allows an attacker to inject operating system commands remotely, potentially leading to system compromise or data leakage. This report provides an in-depth analysis of the vulnerability, its impact, and recommended mitigations.

Vulnerability Summary

CVE ID: CVE-2024-0296
Severity: Critical (CVSS score 7.3)
Attack Vector: Network
Privileges Required: None
User Interaction: None
Impact: Potential system compromise or data leakage

Affected Products

Product | Affected Versions

Totolink N200RE | 9.3.5u.6139_B20201216

How the Exploit Works

The exploit takes advantage of a flaw in the NTPSyncWithHost function of the /cgi-bin/cstecgi.cgi file. By manipulating the ‘host_time’ argument, an attacker can inject and execute arbitrary operating system commands. This can be done remotely and without any user interaction, making it a highly dangerous vulnerability.

Conceptual Example Code

Here is a conceptual example of how the vulnerability might be exploited. This example uses a HTTP POST request with a malicious payload:

POST /cgi-bin/cstecgi.cgi HTTP/1.1
Host: target.example.com
Content-Type: application/x-www-form-urlencoded
function=NTPSyncWithHost&host_time=;rm -rf /*;

In this example, the ‘host_time’ parameter is followed by a semicolon (;), allowing the attacker to append an arbitrary command like ‘rm -rf /*’, which would delete all files on the target system.

Mitigation

Users of Totolink N200RE 9.3.5u.6139_B20201216 are advised to apply the vendor’s patch as soon as possible. If the patch cannot be applied immediately, the use of a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can provide temporary mitigation. However, these measures will not fully address the vulnerability and may only limit its impact. It is strongly recommended to apply the patch as soon as it is available.