CVE-2021-34793 : Security Advisory and Response
Learn about CVE-2021-34793, a high-severity vulnerability affecting Cisco ASA & FTD Software in transparent mode, allowing network disruption through MAC address table poisoning.
A vulnerability has been discovered in the TCP Normalizer of Cisco Adaptive Security Appliance (ASA) Software and Firepower Threat Defense (FTD) Software operating in transparent mode. This flaw could be exploited by an unauthenticated remote attacker to poison MAC address tables, leading to a denial of service (DoS) situation.
Understanding CVE-2021-34793
This section will delve into the details of the CVE-2021-34793 vulnerability, including its impact and technical aspects.
What is CVE-2021-34793?
The vulnerability in Cisco ASA and FTD Software allows attackers to disrupt neighboring network devices by poisoning MAC address tables through crafted TCP segments.
The Impact of CVE-2021-34793
Exploiting this vulnerability could result in a denial of service (DoS) scenario due to the incorrect handling of TCP segments in transparent mode, potentially causing network disruptions.
Technical Details of CVE-2021-34793
Let's explore the technical aspects related to CVE-2021-34793 to understand the vulnerability better.
Vulnerability Description
The vulnerability arises from the mishandling of certain TCP segments when the affected device functions in transparent mode, enabling attackers to poison MAC address tables across adjacent devices.
Affected Systems and Versions
The affected products include Cisco Adaptive Security Appliance (ASA) Software. The specific impacted version details were not provided.
Exploitation Mechanism
By sending a carefully crafted TCP segment through the impacted device, an attacker can poison MAC address tables on neighboring devices and disrupt network operations.
Mitigation and Prevention
Discover the necessary steps to mitigate the risks associated with CVE-2021-34793 and prevent potential exploitation.
Immediate Steps to Take
It is crucial to apply security patches promptly after release to prevent exploitation of this vulnerability.
Long-Term Security Practices
Ensuring network segmentation, access controls, and regular security updates can enhance overall network resilience against such vulnerabilities.
Patching and Updates
Stay informed about security advisories and updates from Cisco to patch the vulnerability effectively and prevent possible DoS scenarios.