CVE-2018-0281 in Firepower System Software
Summary
by MITRE
A vulnerability in the detection engine of Cisco Firepower System Software could allow an unauthenticated, remote attacker to restart an instance of the Snort detection engine on an affected device, resulting in a brief denial of service (DoS) condition. The vulnerability is due to the incorrect handling of a Transport Layer Security (TLS) extension during TLS connection setup for the affected software. An attacker could exploit this vulnerability by sending a crafted TLS connection setup request to an affected device. A successful exploit could allow the attacker to cause the Snort detection engine on the affected device to restart, resulting in a DoS condition. Cisco Bug IDs: CSCvg97808.
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Analysis
by VulDB Data Team • 11/26/2024
The vulnerability described in CVE-2018-0281 represents a significant security weakness within Cisco Firepower System Software that impacts the integrity and availability of network security operations. This flaw specifically targets the Snort detection engine component, which serves as a critical intrusion detection and prevention system within the Cisco Firepower platform. The vulnerability stems from improper handling of Transport Layer Security extensions during the TLS connection establishment process, creating an exploitable condition that can be leveraged by remote attackers without requiring authentication credentials.
The technical implementation of this vulnerability occurs during the TLS handshake process where the affected software fails to properly validate or process specific TLS extension parameters. When an attacker crafts a malicious TLS connection setup request containing specially formatted extension data, the system's detection engine becomes susceptible to manipulation. This improper TLS extension handling causes the Snort detection engine to crash or restart unexpectedly, leading to a temporary disruption of network monitoring capabilities. The flaw essentially creates a condition where legitimate security operations are interrupted through malicious manipulation of the TLS protocol stack.
From an operational impact perspective, this vulnerability presents a clear denial of service threat that can severely compromise network security monitoring capabilities. The restart of the Snort detection engine creates a window where network traffic is not being properly inspected for potential threats, leaving the network vulnerable to attacks that might otherwise be detected. The brief duration of the DoS condition does not diminish its significance since even temporary interruptions in security monitoring can allow malicious actors to exploit the network during the vulnerable period. This vulnerability particularly affects organizations relying on continuous network monitoring for threat detection and incident response.
The vulnerability aligns with CWE-200, which covers "Information Exposure," and CWE-347, addressing "Improper Verification of Cryptographic Signature," as the flaw involves inadequate validation of TLS extensions that should be properly authenticated and verified. Additionally, this vulnerability maps to ATT&CK technique T1499.004, "Endpoint Denial of Service," which encompasses attacks that target system availability through disruption of endpoint services. Organizations should consider implementing network segmentation strategies to isolate critical security infrastructure and deploy monitoring solutions that can detect unusual Snort engine restart patterns. Cisco has released software updates addressing this vulnerability, and organizations should prioritize applying these patches to maintain system integrity and prevent potential exploitation.
The exploitation of this vulnerability demonstrates the importance of proper TLS implementation and validation within security appliances. Network security devices must maintain robust handling of cryptographic protocols to prevent manipulation that could lead to service disruption. This case highlights the need for comprehensive testing of protocol implementations and the critical role of timely patch management in maintaining network security posture. Organizations should also consider implementing additional monitoring and alerting mechanisms to detect anomalous behavior in their security infrastructure that could indicate exploitation attempts.
The vulnerability underscores the broader challenge of maintaining security in complex network environments where multiple protocols interact. The interaction between TLS protocol handling and detection engine operations creates a unique attack surface that requires careful attention to protocol validation and error handling. Security teams should conduct regular vulnerability assessments and penetration testing to identify similar weaknesses in their network infrastructure. Proper incident response procedures should include specific protocols for handling detection engine restarts and monitoring for potential exploitation of similar protocol-based vulnerabilities.