Firepower Threat Defense
CVE-2024-20353
HIGH
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A06:2021 - Vulnerable and Outdated Components
ASVS 5.0
V14 - Configuration Dependency management, component inventory
MITRE ATT&CK
1 technique across 1 tactic: Impact The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Impact | High risk (CVSS 8.6). The ArcaneDoor campaign targeted government organizations worldwide, deploying custom implants (Line Dancer and Line Runner) on Cisco ASA devices for persistent access and traffic interception. |
| Exploit ScenarioDerived | The ArcaneDoor threat actor exploited multiple Cisco ASA zero-days to gain initial access to firewall devices at government facilities. CVE-2024-20353 was used to crash and reload devices as part of the exploitation chain, while other vulnerabilities enabled persistent implant deployment. |
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Alert meAnalysisAIv1 – Mar 26, 2026
Cisco ASA and FTD management and VPN web servers contain a vulnerability causing device reload through incomplete error checking, exploited alongside CVE-2024-20359 by state-sponsored actors in the 'ArcaneDoor' campaign.
Earlier versions of this analysis (1)
A vulnerability in Cisco ASA/FTD web servers allows unauthenticated remote attackers to cause device crashes through crafted requests. Part of the 'ArcaneDoor' campaign attributed to a sophisticated state-sponsored actor.
RemediationAI
Apply Cisco security updates. Run Cisco's Integrity Checker to verify ASA firmware. Check for ArcaneDoor indicators of compromise. Implement out-of-band management for ASA devices.
Affects your stack
Find out whether the stacks and servers you run are on an affected version.
Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
The CWE-835 infinite loop vulnerability in ASA/FTD's web server request handling allows specially crafted requests to trigger incomplete error processing, causing the device to reload. This DoS capability was used as part of a larger campaign involving device compromise.
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Severity by source
AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
Lifecycle Timeline
3DescriptionNVD
A vulnerability in the management and VPN web servers for Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the device to reload unexpectedly, resulting in a denial of service (DoS) condition. This vulnerability is due to incomplete error checking when parsing an HTTP header. An attacker could exploit this vulnerability by sending a crafted HTTP request to a targeted web server on a device. A successful exploit could allow the attacker to cause a DoS condition when the device reloads.
Executive ViewAI
CVE-2024-20353 presents significant security risk rated CVSS 8.6. Successful exploitation could significantly impact the confidentiality, integrity, or availability of affected systems. This vulnerability is actively exploited in the wild (KEV-listed) and requires immediate remediation. Immediate patching is required per CISA KEV mandate.
Apply vendor patch. If immediate patching is not feasible: (1) Implement network-level access controls to limit exposure; (2) Enable enhanced monitoring and alerting; (3) Apply principle of least privilege.
Threat Intelligence Overview
NVD
CVE.org
CISA KEV
EPSS
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.
Affected Products (CPE)NVD
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GitHub PoC
Exploit-DB