CVE-2019-1832 in Firepower Threat Defense
Summary
by MITRE
A vulnerability in the detection engine of Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to bypass configured access control policies. The vulnerability is due to improper validation of ICMP packets. An attacker could exploit this vulnerability by sending crafted ICMP packets to the affected device. A successful exploit could allow the attacker to bypass configured access control policies.
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Analysis
by VulDB Data Team • 11/26/2024
The vulnerability identified as CVE-2019-1832 represents a critical weakness in Cisco Firepower Threat Defense software that fundamentally compromises network security controls. This issue resides within the detection engine of the FTD platform, which serves as the core component responsible for identifying and enforcing access control policies. The flaw specifically manifests in the improper validation of Internet Control Message Protocol packets, creating a pathway for unauthorized network access that bypasses established security measures. Organizations relying on Cisco Firepower for network protection face significant risk as this vulnerability can be exploited remotely without authentication, undermining the fundamental purpose of firewall and intrusion prevention systems.
The technical root cause of this vulnerability stems from inadequate input validation within the ICMP packet processing logic of the FTD software. When the system receives ICMP packets, it fails to properly validate the packet structure and content, allowing malformed or specially crafted packets to slip through security checks. This weakness enables attackers to manipulate the detection engine's behavior by sending specifically designed ICMP packets that exploit the validation gap. The vulnerability is particularly dangerous because ICMP packets are commonly used for network diagnostics and are typically not subject to strict filtering rules, making them an ideal vector for exploitation. This flaw aligns with CWE-20, which describes improper input validation, and represents a classic example of how insufficient protocol handling can create security bypass opportunities.
Operationally, the impact of CVE-2019-1832 extends beyond simple network access bypass to potentially compromise the entire security posture of affected organizations. An attacker who successfully exploits this vulnerability can effectively render configured access control policies ineffective, allowing unauthorized traffic to flow through the network without detection or restriction. This could enable lateral movement within the network, data exfiltration, or the establishment of persistent access points. The remote exploitation capability means that attackers do not need physical access or network credentials to exploit the vulnerability, making it particularly attractive for automated attacks. From an adversary perspective, this vulnerability maps to ATT&CK technique T1071.004 for application layer protocol usage and T1566 for social engineering, as it allows attackers to bypass network controls that would normally prevent such activities.
Organizations must implement immediate mitigations to address this vulnerability, including applying the latest Cisco security patches and updates as released through their official advisory channels. Network administrators should also consider implementing additional monitoring and logging of ICMP traffic to detect potential exploitation attempts. The Cisco Firepower platform should be configured with strict ICMP filtering rules that limit the types of ICMP packets permitted through the system. Security teams should conduct thorough network assessments to identify any unauthorized access that may have occurred during the vulnerability window, and implement network segmentation strategies to limit potential lateral movement if exploitation occurs. Additionally, organizations should review their incident response procedures to ensure readiness for potential exploitation of this type of vulnerability, as it represents a significant threat to network security infrastructure.