CVE-2018-0385 in Firepower System Software
Summary
by MITRE
A vulnerability in the detection engine parsing of Security Socket Layer (SSL) protocol packets for Cisco Firepower System Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition due to the Snort process unexpectedly restarting. The vulnerability is due to improper input handling of the SSL traffic. An attacker could exploit this vulnerability by sending a crafted SSL traffic to the detection engine on the targeted device. An exploit could allow the attacker to cause a DoS condition if the Snort process restarts and traffic inspection is bypassed or traffic is dropped. Cisco Bug IDs: CSCvi36434.
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Analysis
by VulDB Data Team • 11/26/2024
The vulnerability described in CVE-2018-0385 represents a critical flaw in Cisco Firepower System Software's handling of SSL protocol packets within its detection engine. This issue specifically targets the Snort intrusion detection system component that operates as part of Cisco's network security infrastructure. The vulnerability stems from inadequate input validation mechanisms within the SSL packet parsing functionality, creating a pathway for malicious actors to disrupt normal network operations through carefully crafted network traffic. The affected system processes SSL traffic through a detection engine that fails to properly sanitize incoming packets, leading to unexpected behavior when malformed or specially constructed SSL data is received.
The technical exploitation of this vulnerability occurs through the manipulation of SSL protocol packet structures that the detection engine processes. When an attacker sends specifically crafted SSL traffic to the targeted Firepower device, the system's Snort process encounters malformed input that triggers an unexpected restart condition. This restart represents a fundamental failure in the system's error handling mechanisms, where the detection engine does not properly validate or sanitize SSL packet contents before processing them. The vulnerability demonstrates poor input validation practices that align with CWE-20, which addresses "Improper Input Validation" in software security implementations. The flaw essentially allows an attacker to inject malformed data that causes the Snort process to crash and restart, effectively disrupting the device's ability to perform network traffic inspection.
The operational impact of this vulnerability extends beyond simple service disruption to create a significant security risk for organizations relying on Cisco Firepower systems for network protection. When the Snort process restarts due to the vulnerability, the device experiences a complete bypass of traffic inspection capabilities, leaving the network exposed to potential threats that would normally be detected by the system. This creates a window of vulnerability where malicious traffic can pass through the network security infrastructure without proper monitoring or filtering. The DoS condition effectively neutralizes the security protections that the device is designed to provide, potentially allowing attackers to establish persistent access or conduct further malicious activities. The restart of the Snort process also results in traffic being dropped or improperly handled, creating additional network instability and potential data loss.
Organizations affected by this vulnerability should implement immediate mitigation strategies to protect their network infrastructure. The primary recommended action involves applying the relevant Cisco security patches and updates that address the specific input validation issues within the SSL detection engine. Network administrators should also consider implementing network segmentation and access controls to limit exposure of vulnerable devices to untrusted network segments. Monitoring and logging should be enhanced to detect potential exploitation attempts, including unusual patterns of SSL traffic that might indicate attempted exploitation. The vulnerability's characteristics align with ATT&CK technique T1499.004, which covers "Evasion: File System Content Removal" and related network disruption tactics that attackers might employ to compromise system availability. Additionally, this issue demonstrates the importance of robust input validation and error handling in security-critical systems, as outlined in security frameworks such as the OWASP Top Ten and NIST cybersecurity guidelines. Organizations should also conduct thorough vulnerability assessments to identify other potential input validation weaknesses in their network security infrastructure and implement comprehensive security testing procedures to prevent similar issues from occurring in the future.