CVE-2021-4242 - Critical Vulnerability Found in Sapido Router Models (BR270n, BRC76n, GR297, RB1732)

A recent discovery exposed a critical vulnerability in multiple Sapido router models, namely BR270n, BRC76n, GR297, and RB1732. This vulnerability is related to an unknown functionality in the ip/syscmd.htm file and has been classified as an operating system (OS) command injection. Identified as VDB-214592, this exploit affects routers' performance and can potentially compromise the security of connected devices.

The severity of this issue is alarming, as the attack can be carried out remotely. An attacker can execute arbitrary OS-level commands on the vulnerable router, which gives the attacker immense control over the device. Furthermore, the exploit has been disclosed to the public, which means attackers can potentially be aware of its existence and may already be using it.

To help those who are trying to understand this vulnerability and prevent potential exploits, below is an example of the code snippet associated with CVE-2021-4242:

POST /ip/syscmd.htm HTTP/1.1
Host: [TARGET]
Accept: */*
Content-Type: application/x-www-form-urlencoded; charset=UTF-8
Content-Length: [LENGTH]

submit_button=sysCmd&sysCmd=%3b%20[YOUR_OS_COMMAND]%20%2f%20%26&submit_type=pcmd&_cbid=...

To grasp the extent of this issue, please refer to the original references and sources

- Vulnerability Database: VDB-214592
- Vulnerability Details: OS Command Injection

Exploit Details

The OS command injection vulnerability originates from improper input validation. The attacker can manipulate the router's OS by injecting arbitrary commands through the ip/syscmd.htm file. These commands can compromise or disrupt the router's functionalities, thereby impacting the security, performance, and overall stability of home and business networks. The attack vector is through HTTP POST requests, which allows the attacker to remotely exploit the vulnerability.

To mitigate the risk, it is important to ensure that the routers are running on the latest firmware, and any applicable patches have been applied. Users should also employ proper network security practices to prevent unauthorized access to their routers and connected devices.

It is essential for router manufacturers, researchers, and users alike to take this issue seriously and work together to reduce the risk that CVE-2021-4242 poses to home and business networks. By remaining vigilant and staying informed, we can protect our routers and keep our networks secure.

Timeline

Published on: 11/30/2022 14:15:00 UTC
Last modified on: 12/02/2022 18:29:00 UTC