CVE-2023-20086 Explained : Impact and Mitigation

This CVE-2023-20086 involves a vulnerability in ICMPv6 processing of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software, which could lead to a denial of service (DoS) attack by an unauthenticated, remote attacker. The flaw is a result of improper handling of ICMPv6 messages, allowing an attacker to trigger a system reload, causing a DoS condition.

Understanding CVE-2023-20086

This section will provide a detailed overview of the CVE-2023-20086 vulnerability, including its impact, technical details, affected systems, and mitigation steps.

What is CVE-2023-20086?

The vulnerability in CVE-2023-20086 pertains to the mishandling of ICMPv6 messages in Cisco ASA Software and Cisco FTD Software, enabling attackers to exploit the flaw remotely and disrupt the normal operation of the affected systems by causing a DoS condition.

The Impact of CVE-2023-20086

The impact of CVE-2023-20086 can result in a denial of service (DoS) scenario on targeted Cisco ASA or FTD systems with IPv6 enabled. An attacker could exploit this vulnerability by sending crafted ICMPv6 messages, leading to a system reload and subsequent unavailability of services.

Technical Details of CVE-2023-20086

The technical aspects of CVE-2023-20086 encompass the vulnerability description, affected systems and versions, and exploitation mechanism.

Vulnerability Description

The vulnerability in ICMPv6 processing of Cisco ASA Software and Cisco FTD Software results from the incorrect handling of ICMPv6 messages, allowing unauthenticated attackers to trigger a system reload and cause a denial of service (DoS) condition.

Affected Systems and Versions

Various versions of Cisco ASA Software and Cisco FTD Software are affected by CVE-2023-20086, ranging from 9.8.1 to 9.19.1 for ASA Software and 6.2.3 to 7.3.1 for FTD Software. These versions are susceptible to exploitation through crafted ICMPv6 messages.

Exploitation Mechanism

Exploiting CVE-2023-20086 involves sending maliciously crafted ICMPv6 messages to targeted Cisco ASA or FTD systems with IPv6 enabled. Upon successful exploitation, the attacker can cause the device to reload, leading to a denial of service (DoS) situation.

Mitigation and Prevention

This section outlines the necessary steps to mitigate and prevent the exploitation of CVE-2023-20086, ensuring the security of Cisco ASA and FTD systems.

Immediate Steps to Take

Disable IPv6 if not required to mitigate the risk of exploitation via ICMPv6 messages.
Implement access control lists (ACLs) to filter out potentially malicious ICMPv6 traffic.
Regularly monitor and update the affected software versions to address security vulnerabilities.

Long-Term Security Practices

Keep systems up to date with the latest security patches and software updates provided by Cisco.
Conduct regular security assessments and audits to identify and address potential vulnerabilities proactively.
Employ network segmentation and proper security configurations to limit the impact of potential attacks.

Patching and Updates

Ensure timely application of patches and updates released by Cisco for the affected versions of ASA Software and FTD Software to remediate the vulnerability and enhance the overall security posture of the systems.