CVE-2023-33237: Improper Authentication Vulnerability in TN-590 Series Firmware v3.3 and Prior - Exploit Details and Solutions

The CVE-2023-33237 vulnerability has been identified in TN-590 Series firmware version v3.3 and prior. This vulnerability is the result of improper authentication in the web API handler. In this long-read post, we will walk through the details of the vulnerability, provide code snippets to understand the impact and provide links to original references, and discuss potential exploitations by malicious actors.

Vulnerability Details

The TN-590 Series firmware version v3.3 and prior is vulnerable to an improper-authentication vulnerability. This vulnerability arises from inadequate authentication measures that have been implemented in the web API handler. Due to this weakness, low-privileged APIs are allowed to execute restricted actions that should only be available to high-privileged APIs. This presents a potential risk of unauthorized exploitation by malicious actors.

Affected Products

TN-590 Series firmware version v3.3 and prior

Original References

1. TN-590 Series Firmware Advisory – v3.3 and prior
2. CVE-2023-33237 - National Vulnerability Database

Code Snippet

The following Python code snippet demonstrates how a low-privileged API can exploit this improper authentication vulnerability to execute restricted actions:

import requests

URL = "https://target_ip_address/api";
LOW_PRIV_API_KEY = "low_priv_key"

# Payload for restricted action that should be accessible only to high-privileged APIs
payload = {
    "action": "restricted_action",
    "parameters": {...}
}

headers = {
    "Authorization": f"Bearer {LOW_PRIV_API_KEY}",
    "Content-Type": "application/json"
}

response = requests.post(URL, headers=headers, json=payload)

if response.status_code == 200:
    print("Restricted action executed successfully")
else:
    print("Failed to exploit the vulnerability")

The code above uses the requests library to send an HTTP POST request to the vulnerable API with the low-privileged API key. If the vulnerable API allows the low-privileged API to execute the restricted action, it confirms the presence of the improper authentication vulnerability.

Exploit Details

Exploiting this vulnerability allows an attacker with low-privileged API access to execute actions meant to be restricted only to high-privileged API access. This can lead to unauthorized access, data theft, service disruption, and potentially worse outcomes depending on the restricted actions available in the target system. Malicious actors can potentially leverage this vulnerability to escalate their privileges and compromise the affected system further.

Mitigation and Solution

To address this improper authentication vulnerability, affected users should update their TN-590 Series firmware to the latest version that implements proper authentication measures. Firmware updates can be obtained through the manufacturer's website or support channels.

Additionally, organizations should monitor their API usage and implement strong access control measures to ensure that only authorized users and applications can interact with sensitive APIs.

Conclusion

The CVE-2023-33237 vulnerability presents a significant risk to organizations using TN-590 Series firmware version v3.3 and prior due to improper authentication measures in the web API handler. Understanding the details of this vulnerability, as well as the potential exploits and mitigations, is crucial to maintaining a secure environment. By staying informed and taking necessary action to remediate vulnerabilities in a timely manner, organizations can greatly reduce their risk of falling victim to malicious actors.

Timeline

Published on: 08/17/2023 02:15:00 UTC
Last modified on: 08/22/2023 19:10:00 UTC