CVE-2023-20168 : Security Advisory and Response

This CVE, assigned by Cisco, was published on August 23, 2023. It pertains to a vulnerability in TACACS+ and RADIUS remote authentication for Cisco NX-OS Software that could allow an attacker to cause a denial of service (DoS) by triggering an affected device to reload unexpectedly.

Understanding CVE-2023-20168

This vulnerability in Cisco NX-OS Software stems from incorrect input validation during authentication attempts when the directed request option is enabled for TACACS+ or RADIUS.

What is CVE-2023-20168?

The vulnerability presents an opportunity for an unauthenticated, local attacker to input a maliciously crafted string at the login prompt of an affected device. A successful exploitation of CVE-2023-20168 could result in the affected device reloading unexpectedly, leading to a denial of service situation.

The Impact of CVE-2023-20168

The impact of this vulnerability is categorized as HIGH, with a base score of 7.1. The availability of the affected system is significantly impacted as an attacker can exploit this flaw to cause the device to reload unexpectedly, thereby disrupting its services.

Technical Details of CVE-2023-20168

This vulnerability affects various versions of Cisco NX-OS Software. The incorrect input validation issue when processing authentication attempts affects numerous versions, making a wide range of systems vulnerable.

Vulnerability Description

The vulnerability arises due to incorrect input validation in processing authentication attempts when the directed request option is enabled for TACACS+ or RADIUS.

Affected Systems and Versions

Numerous versions of Cisco NX-OS Software are impacted by this vulnerability, ranging from 4.2(1)SV1(4) to 10.3(2).

Exploitation Mechanism

An attacker can exploit this vulnerability by entering a specifically crafted string at the login prompt of an affected device, triggering a reload and causing a denial of service.

Mitigation and Prevention

To mitigate the risks associated with CVE-2023-20168, immediate steps should be taken along with the implementation of long-term security practices and timely patching and updates.

Immediate Steps to Take

Disable the directed request option for TACACS+ or RADIUS if not necessary.
Monitor network traffic for any suspicious activities.
Implement strong network access controls.

Long-Term Security Practices

Regularly update and patch systems to protect against known vulnerabilities.
Conduct security audits and assessments periodically.
Educate users and administrators on best security practices.

Patching and Updates

Ensure that the affected systems are updated with the latest patches provided by Cisco to address the vulnerability effectively. Regularly check for security advisories and updates from the vendor to stay protected against potential threats.