CVE-2021-45756 Explained : Impact and Mitigation

Asus RT-AC68U <3.0.0.4.385.20633 and RT-AC5300 <3.0.0.4.384.82072 are affected by a buffer overflow in blocking_request.cgi.

Understanding CVE-2021-45756

What is CVE-2021-45756?

This CVE describes a buffer overflow vulnerability found in Asus RT-AC68U and RT-AC5300 routers in the blocking_request.cgi script.

The Impact of CVE-2021-45756

The buffer overflow vulnerability could allow remote attackers to execute arbitrary code or cause a denial of service on the affected routers.

Technical Details of CVE-2021-45756

Vulnerability Description

The vulnerability exists in the blocking_request.cgi script in Asus RT-AC68U and RT-AC5300 routers, allowing attackers to trigger a buffer overflow.

Affected Systems and Versions

Asus RT-AC68U <3.0.0.4.385.20633
Asus RT-AC5300 <3.0.0.4.384.82072

Exploitation Mechanism

Attackers can exploit this vulnerability by sending crafted requests to the blocking_request.cgi script, causing a buffer overflow and potentially executing malicious code.

Mitigation and Prevention

Immediate Steps to Take

Apply security patches provided by Asus as soon as they are available.
Restrict external access to the routers by using firewalls or access control lists.
Monitor network traffic for any suspicious activities or unauthorized access.

Long-Term Security Practices

Regularly update router firmware to ensure the latest security fixes are in place.
Implement strong and unique passwords for router administration to prevent unauthorized access.

Patching and Updates

Ensure to regularly check for firmware updates on the Asus official website and apply them promptly to mitigate this vulnerability.