CVE-2024-20408 in ASA
Summary
by MITRE • 10/23/2024
A vulnerability in the Dynamic Access Policies (DAP) feature of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an authenticated, remote attacker to cause an affected device to reload unexpectedly. To exploit this vulnerability, an attacker would need valid remote access VPN user credentials on the affected device.
This vulnerability is due to improper validation of data in HTTPS POST requests. An attacker could exploit this vulnerability by sending a crafted HTTPS POST request to an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a denial of service (DoS) condition.
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Analysis
by VulDB Data Team • 08/01/2025
The vulnerability identified as CVE-2024-20408 resides within the Dynamic Access Policies feature of Cisco Adaptive Security Appliance software and Cisco Firepower Threat Defense software, representing a significant security weakness that could be exploited by authenticated remote attackers. This flaw specifically targets the validation mechanisms implemented within the HTTPS POST request processing functionality, creating a pathway for malicious actors to disrupt service availability. The vulnerability requires minimal prerequisites for exploitation since only valid remote access VPN credentials are necessary to initiate the attack vector, making it particularly concerning for organizations that rely heavily on VPN connectivity for remote access.
The technical root cause of this vulnerability stems from inadequate input validation within the HTTPS POST request handling process, which falls under the category of improper validation of data as classified by CWE-20. When an attacker crafts and submits a malicious POST request to the affected device, the system fails to properly sanitize or validate the incoming data before processing it within the Dynamic Access Policies framework. This insufficient validation creates an opportunity for the attacker to manipulate the device's internal state through carefully constructed payloads that trigger unexpected behavior in the software's processing logic. The vulnerability manifests as an unexpected device reload, which constitutes a denial of service condition that can severely impact network availability and business continuity.
The operational impact of this vulnerability extends beyond simple service disruption, as it represents a potential entry point for more sophisticated attacks that could leverage the device reload as a stepping stone for further exploitation. Organizations utilizing Cisco ASA and FTD appliances with Dynamic Access Policies enabled face a heightened risk of service interruption, particularly during critical business hours or when remote access is essential for operations. The vulnerability's remote exploitability means that attackers can target affected devices from outside the network perimeter, eliminating the need for physical access or insider knowledge. This characteristic places significant strain on security operations teams who must monitor and respond to potential exploitation attempts while maintaining service availability for legitimate users.
Mitigation strategies for CVE-2024-20408 should prioritize immediate software updates from Cisco to address the validation flaw in HTTPS POST request handling. Organizations should also implement network segmentation and access controls to limit the potential impact of exploitation, ensuring that only authorized users can access the affected services. Security monitoring should be enhanced to detect unusual patterns in HTTPS POST requests that might indicate exploitation attempts, while network administrators should consider implementing additional logging and alerting mechanisms for Dynamic Access Policies functionality. The vulnerability's classification under ATT&CK technique T1499.004 for network denial of service indicates that organizations should also prepare incident response procedures that account for potential exploitation and implement proper network resilience measures to minimize the impact of such attacks on overall network availability.