CVE-2021-34781

Cisco Firepower Threat Defense Software SSH Connections Denial of Service Vulnerability

Published Oct 27, 2021 CVSS 3.1 · 8.6 High EPSS 1.4% KEV · Not listed
Description
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. This vulnerability is due to a lack of proper error handling when an SSH session fails to be established. An attacker could exploit this vulnerability by sending a high rate of crafted SSH connections to the instance. A successful exploit could allow the attacker to cause resource exhaustion, which causes a DoS condition on the affected device. The device must be manually reloaded to recover.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
EUVD EUVD EUVD-2021-21431 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. This vulnerability is due to a lack of proper error handling when an SSH session fails to be established. An attacker could exploit this vulnerability by sending a high rate of crafted SSH connections to the instance. A successful exploit could allow the attacker to cause resource exhaustion, which causes a DoS condition on the affected device. The device must be manually reloaded to recover.
History
Type Values Removed Values Added
First Time appeared Cisco secure Firewall Threat Defense
CPEs cpe:2.3:a:cisco:firepower_threat_defense:*:*:*:*:*:*:*:* cpe:2.3:a:cisco:secure_firewall_threat_defense:*:*:*:*:*:*:*:*
Vendors & Products Cisco firepower Threat Defense
Cisco secure Firewall Threat Defense
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
cisco
Published
Updated
Nov 7, 2024, 9:46 PM
Reserved
Jun 15, 2021, 12:00 AM
Status
Modified
Published
Oct 27, 2021, 7:15 PM
Modified
Aug 11, 2026, 7:33 PM