CVE-2018-0384 in FireSIGHT System Software
Summary
by MITRE
A vulnerability in the detection engine of Cisco FireSIGHT System Software could allow an unauthenticated, remote attacker to bypass a URL-based access control policy that is configured to block traffic for an affected system. The vulnerability exists because the affected software incorrectly handles TCP packets that are received out of order when a TCP SYN retransmission is issued. An attacker could exploit this vulnerability by sending a maliciously crafted connection through an affected device. A successful exploit could allow the attacker to bypass a URL-based access control policy that is configured to block traffic for the affected system. Cisco Bug IDs: CSCvh84511.
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Analysis
by VulDB Data Team • 11/26/2024
The vulnerability identified as CVE-2018-0384 resides within the detection engine of Cisco FireSIGHT System Software, representing a critical security flaw that undermines the integrity of URL-based access control policies. This weakness specifically manifests when the system processes TCP packets that arrive out of sequence during TCP SYN retransmission scenarios, creating a pathway for unauthorized network access that bypasses configured security measures. The flaw fundamentally compromises the software's ability to properly validate incoming network traffic, potentially allowing malicious actors to circumvent protection mechanisms that should prevent access to specific URLs or network resources.
The technical root cause of this vulnerability stems from improper handling of TCP packet ordering within the FireSIGHT system's processing pipeline. When TCP SYN retransmissions occur, the software fails to correctly interpret and process packets that arrive out of sequence, leading to a misclassification of network connections. This misinterpretation allows an attacker to craft specifically designed TCP packets that exploit the system's failure to properly validate connection states, effectively creating a bypass mechanism for URL filtering policies. The vulnerability operates at the transport layer of the network stack, making it particularly dangerous as it can be exploited without requiring authentication credentials or privileged access to the system.
The operational impact of this vulnerability extends beyond simple policy bypass, as it represents a fundamental failure in the system's security enforcement capabilities. An unauthenticated remote attacker can leverage this weakness to gain unauthorized access to network resources that should be blocked by configured URL filtering rules, potentially leading to data exfiltration, lateral movement within the network, or access to sensitive applications and services. The attack vector requires only the ability to send crafted TCP packets to the affected device, making exploitation relatively straightforward and increasing the potential for widespread impact across organizations relying on Cisco FireSIGHT for network security. This vulnerability directly violates the principle of least privilege and can result in significant security breaches when organizations depend on URL-based access controls for their network protection.
Organizations affected by this vulnerability should implement immediate mitigations including applying the latest Cisco software patches and updates, which address the TCP packet reordering handling issue within the FireSIGHT detection engine. Network administrators should also consider implementing additional monitoring controls to detect unusual TCP packet patterns that may indicate exploitation attempts, while reviewing and validating existing URL-based access control policies to ensure they remain effective. The vulnerability aligns with CWE-129, which addresses improper handling of input validation issues, and can be mapped to ATT&CK technique T1071.004 for application layer protocol tunneling, as attackers may leverage this bypass to establish unauthorized connections through seemingly blocked network paths. Security teams should also conduct comprehensive network assessments to identify any potential exploitation attempts and ensure that alternative security controls remain effective while the primary vulnerability is being addressed through official patches and updates from Cisco.