CVE-2018-0300 in FXOS
Summary
by MITRE
A vulnerability in the process of uploading new application images to Cisco FXOS on the Cisco Firepower 4100 Series Next-Generation Firewall (NGFW) and Firepower 9300 Security Appliance could allow an authenticated, remote attacker using path traversal techniques to create or overwrite arbitrary files on an affected device. The vulnerability is due to insufficient validation during the application image upload process. An attacker could exploit this vulnerability by creating an application image containing malicious code and installing the image on the affected device using the CLI or web-based user interface (web UI). These actions occur prior to signature verification and could allow the attacker to create and execute arbitrary code with root privileges. Note: A missing or invalid signature in the application image will cause the upload process to fail, but does not prevent the exploit. Cisco Bug IDs: CSCvc21901.
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Analysis
by VulDB Data Team • 03/28/2023
The vulnerability identified as CVE-2018-0300 resides within the Cisco Firepower 4100 Series Next-Generation Firewall and Firepower 9300 Security Appliance platforms, specifically affecting the Fabric Extensible Operating System (FXOS) component. This flaw represents a critical path traversal vulnerability that fundamentally compromises the integrity of the device's software update mechanism. The vulnerability stems from inadequate input validation during the application image upload process, creating a pathway for authenticated remote attackers to manipulate the system's file structure through carefully crafted malicious payloads.
The technical exploitation of this vulnerability leverages path traversal techniques to manipulate file creation and overwrite operations within the affected device's filesystem. Attackers can craft specially formatted application images that contain malicious code designed to execute with root privileges upon installation. The vulnerability is particularly dangerous because it operates prior to signature verification processes, meaning that even unsigned or improperly signed images can be successfully uploaded and executed. This timing aspect places the vulnerability at a critical point in the security chain where traditional signature validation mechanisms fail to provide protection against the malicious payload.
From an operational perspective, this vulnerability creates a severe threat landscape for organizations relying on Cisco Firepower appliances for network security. The ability to execute arbitrary code with root privileges effectively grants attackers complete control over the affected devices, enabling them to establish persistent backdoors, exfiltrate sensitive data, or disrupt network operations. The vulnerability's impact is amplified by the fact that exploitation can occur through both command-line interface and web-based user interface, providing multiple attack vectors and reducing the likelihood of detection. Network defenders face significant challenges in identifying such attacks since they appear to be legitimate software installations.
The vulnerability aligns with CWE-22 Path Traversal and CWE-74 Improper Neutralization of Special Elements in Output Used by a Downstream Component, reflecting weaknesses in input validation and output sanitization. From an ATT&CK framework perspective, this vulnerability maps to T1059 Command and Scripting Interpreter and T1078 Valid Accounts, as attackers must first establish authenticated access before exploiting the path traversal mechanism. The exploit chain typically begins with gaining valid credentials, followed by crafting malicious payloads that bypass the signature verification process, and concluding with execution of arbitrary code at the highest privilege level.
Mitigation strategies should focus on immediate patch deployment as provided by Cisco, which addresses the insufficient validation during the application image upload process. Organizations should implement network segmentation to limit access to Firepower appliances and enforce strict access controls using multi-factor authentication. Regular security assessments should include verification of the upload mechanisms and monitoring for anomalous file creation patterns. Additionally, network defenders should establish robust logging and monitoring procedures to detect unauthorized software installations and file system modifications. The vulnerability serves as a reminder of the critical importance of validating all inputs during software update processes and maintaining defense-in-depth strategies that protect against both authenticated and unauthenticated attack vectors.