CVE-2021-40847 : Vulnerability Insights and Analysis

Circle Parental Control Service on NETGEAR routers allows remote code execution via a MitM attack.

Understanding CVE-2021-40847

This CVE discloses a critical vulnerability in the update process of the Circle Parental Control Service on various NETGEAR routers, enabling remote attackers to execute arbitrary code.

What is CVE-2021-40847?

The vulnerability arises from the circlde update daemon, enabled by default on affected routers, downloading unsigned, cleartext HTTP database updates. Attackers intercepting the updates can craft malicious files, leading to remote code execution.

The Impact of CVE-2021-40847

The CVE affects several NETGEAR router models, including R6400v2, R6700, R6700v3, R6900, R6900P, R7000, R7000P, R7850, R7900, R8000, and RS400. Successful exploitation could grant attackers root-level access to the devices.

Technical Details of CVE-2021-40847

The technical aspects of the vulnerability are as follows:

Vulnerability Description

Attackers can achieve remote code execution through crafted database files.

Affected Systems and Versions

NETGEAR routers including R6400v2, R6700, R6700v3, R6900, R6900P, R7000, R7000P, R7850, R7900, R8000, and RS400.

Exploitation Mechanism

Attackers perform a MitM attack to intercept cleartext database updates and replace them with malicious files.

Mitigation and Prevention

Immediate steps to mitigate the vulnerability:

Disable remote access and update mechanisms if not needed
Implement strong network segmentation

Long-Term Security Practices

Regularly update router firmware
Use encrypted communication protocols

Patching and Updates

Ensure routers are updated with the latest firmware provided by NETGEAR to address the vulnerability.