CVE-2019-1696 in Firepower Threat Defense
Summary
by MITRE
Multiple vulnerabilities in the Server Message Block (SMB) Protocol preprocessor detection engine for Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, adjacent or remote attacker to cause a denial of service (DoS) condition. For more information about these vulnerabilities, see the Details section of this advisory.
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Analysis
by VulDB Data Team • 11/26/2024
The vulnerability identified as CVE-2019-1696 affects the Server Message Block SMB Protocol preprocessor detection engine within Cisco Firepower Threat Defense software, representing a significant security weakness that can be exploited by unauthenticated attackers. This issue specifically targets the processing logic responsible for analyzing SMB protocol traffic, creating potential pathways for malicious actors to disrupt network operations. The vulnerability exists in the way the FTD software handles SMB protocol detection, which is a critical component for network security monitoring and threat detection.
The technical flaw manifests in the SMB preprocessor engine's inability to properly handle certain malformed or unexpected SMB protocol packets, leading to potential buffer overflows, memory corruption, or other processing errors that can result in system instability. This vulnerability is particularly concerning because it affects the core protocol detection capabilities of the Firepower system, meaning that an attacker could potentially trigger a denial of service condition simply by sending specially crafted SMB traffic to the affected device. The attack vector can be either adjacent network access or remote exploitation depending on the specific implementation details and network configuration.
The operational impact of CVE-2019-1696 extends beyond simple service disruption, as it can compromise the integrity of the entire network security infrastructure. When the SMB preprocessor engine crashes or becomes unresponsive due to this vulnerability, the Firepower device may fail to properly monitor or filter SMB traffic, potentially allowing malicious SMB activities to go undetected while the device itself is rendered ineffective. This creates a dangerous scenario where network security is simultaneously weakened and disrupted, leaving organizations vulnerable to both the original threat and additional attacks that exploit the compromised security appliance.
Cisco Firepower Threat Defense systems running affected software versions are at risk, with the vulnerability being classified under CWE-121 for heap-based buffer overflow conditions and potentially CWE-122 for stack-based buffer overflows depending on the specific implementation. The attack patterns align with techniques described in the MITRE ATT&CK framework under the T1498 tactic for network denial of service, where adversaries exploit weaknesses in network infrastructure to disrupt availability of services. Organizations should implement immediate mitigations including applying the latest security patches from Cisco, implementing network segmentation to limit access to affected systems, and monitoring for unusual SMB traffic patterns that might indicate exploitation attempts. The vulnerability represents a critical weakness in network security appliances that requires prompt attention to maintain operational continuity and security posture.