CVE-2021-34781 Explained : Impact and Mitigation
Learn about CVE-2021-34781, a vulnerability in Cisco Firepower Threat Defense Software allowing DoS attacks. Understand the impact, affected systems, and mitigation steps.
A vulnerability in the processing of SSH connections for multi-instance deployments of Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on the affected device.
Understanding CVE-2021-34781
This CVE identifies a vulnerability in Cisco Firepower Threat Defense Software that could lead to a DoS attack.
What is CVE-2021-34781?
The vulnerability in the processing of SSH connections in Cisco Firepower Threat Defense (FTD) Software could enable an attacker to create a DoS condition by sending a high rate of crafted SSH connections to the affected device.
The Impact of CVE-2021-34781
The exploitation of this vulnerability could result in resource exhaustion and a denial of service condition on the targeted device, requiring manual reloading to recover.
Technical Details of CVE-2021-34781
This section provides insights into the vulnerability specifics.
Vulnerability Description
The vulnerability arises due to insufficient error handling when an SSH session establishment fails, allowing an attacker to flood the device with malicious SSH connections.
Affected Systems and Versions
The vulnerability affects Cisco Adaptive Security Appliance (ASA) Software and corresponds to all versions.
Exploitation Mechanism
By sending a high volume of malicious SSH connections, the attacker can exhaust resources and trigger a DoS condition.
Mitigation and Prevention
Protecting systems from CVE-2021-34781 requires prompt action and ongoing security measures.
Immediate Steps to Take
Immediately deploy any patches or workarounds provided by Cisco to mitigate the vulnerability's exploitability.
Long-Term Security Practices
Implement security best practices, such as network segmentation and access controls, to reduce the attack surface and mitigate potential threats.
Patching and Updates
Regularly monitor for security updates from Cisco and apply patches promptly to address known vulnerabilities.