CVE-2018-0453 in Firepower Threat Defense
Summary
by MITRE
A vulnerability in the Sourcefire tunnel control channel protocol in Cisco Firepower System Software running on Cisco Firepower Threat Defense (FTD) sensors could allow an authenticated, local attacker to execute specific CLI commands with root privileges on the Cisco Firepower Management Center (FMC), or through Cisco FMC on other Firepower sensors and devices that are controlled by the same Cisco FMC. To send the commands, the attacker must have root privileges for at least one affected sensor or the Cisco FMC. The vulnerability exists because the affected software performs insufficient checks for certain CLI commands, if the commands are executed via a Sourcefire tunnel connection. An attacker could exploit this vulnerability by authenticating with root privileges to a Firepower sensor or Cisco FMC, and then sending specific CLI commands to the Cisco FMC or through the Cisco FMC to another Firepower sensor via the Sourcefire tunnel connection. A successful exploit could allow the attacker to modify device configurations or delete files on the device that is running Cisco FMC Software or on any Firepower device that is managed by Cisco FMC.
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Analysis
by VulDB Data Team • 03/30/2020
The vulnerability identified as CVE-2018-0453 represents a critical privilege escalation flaw within Cisco Firepower System Software that affects the Sourcefire tunnel control channel protocol implementation. This weakness exists in Cisco Firepower Threat Defense (FTD) sensors and the associated Cisco Firepower Management Center (FMC) software components. The vulnerability stems from inadequate validation mechanisms within the tunnel control channel that processes specific Command Line Interface commands, creating an exploitable path for authenticated local attackers to gain elevated privileges. The flaw specifically manifests when CLI commands are executed through Sourcefire tunnel connections, bypassing normal access controls and authorization checks that should normally prevent unauthorized privilege escalation.
The technical exploitation of this vulnerability requires an attacker to first establish authentication with root privileges on either a Firepower sensor or the Cisco FMC system itself. Once authenticated, the attacker can leverage the insufficient input validation within the Sourcefire tunnel control channel to send specially crafted CLI commands that are not properly sanitized or validated before execution. This protocol flaw allows the attacker to execute commands with root privileges on the FMC or any other Firepower devices managed by the same FMC instance. The vulnerability's impact extends beyond individual sensors to encompass the entire management domain, as the FMC serves as the central control point for multiple sensors and devices within the network security infrastructure. The affected software architecture fails to implement proper command filtering and validation, creating a direct path for privilege escalation that violates fundamental security principles of least privilege and input sanitization.
The operational consequences of this vulnerability are severe and far-reaching within enterprise network security environments that rely on Cisco Firepower solutions. Successful exploitation enables attackers to perform unauthorized configuration modifications, file deletion operations, and potentially establish persistent access points within the network security infrastructure. This vulnerability directly impacts the integrity and availability of security controls, as attackers can manipulate core network security policies and device configurations. The compromise of the FMC represents a particularly dangerous scenario since this management center controls multiple sensors and devices, allowing a single successful exploit to potentially affect an entire network security ecosystem. Organizations using Cisco Firepower solutions face significant risk of data exfiltration, network disruption, and complete compromise of their security infrastructure, as the vulnerability allows for complete administrative control over managed devices. The attack vector's requirement for only root-level access on one system within the domain makes this vulnerability particularly dangerous for environments where root compromise is possible through other attack vectors.
Mitigation strategies for CVE-2018-0453 should focus on immediate software updates and patches provided by Cisco to address the specific validation flaws in the Sourcefire tunnel control channel implementation. Organizations must implement strict access controls and monitoring of FMC and sensor systems to detect unauthorized root access attempts and suspicious CLI command execution patterns. Network segmentation and privilege separation practices should be enforced to limit the potential impact of any successful exploitation attempts. The vulnerability aligns with CWE-20, which describes improper input validation, and represents a classic example of how inadequate security controls in network management protocols can lead to critical privilege escalation vulnerabilities. From an ATT&CK framework perspective, this vulnerability maps to privilege escalation techniques and command execution capabilities, demonstrating how weaknesses in management protocols can enable adversaries to achieve persistence and maintain access within network security infrastructure. Regular security assessments and vulnerability scanning should be conducted to identify any potential exploitation attempts, while implementing comprehensive audit logging and monitoring of CLI activities on FMC and sensor systems to detect anomalous behavior patterns that may indicate exploitation attempts.