CVE-2023-48784 in FortiOS
Summary
by MITRE • 04/09/2024
A use of externally-controlled format string vulnerability [CWE-134] in FortiOS version 7.4.1 and below, version 7.2.7 and below, version 7.0.14 and below, version 6.4.15 and below command line interface may allow a local privileged attacker with super-admin profile and CLI access to execute arbitrary code or commands via specially crafted requests.
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Analysis
by VulDB Data Team • 01/17/2025
This vulnerability represents a critical use of externally-controlled format string flaw that exists within the command line interface of Fortinet FortiOS devices. The issue stems from improper input validation where the system fails to properly sanitize user-supplied data before using it in format string operations. This weakness allows attackers to manipulate format specifiers and potentially inject malicious code into the system. The vulnerability affects multiple versions of FortiOS including 7.4.1 and below, 7.2.7 and below, 7.0.14 and below, and 6.4.15 and below, making it particularly concerning given the widespread deployment of these older versions across enterprise networks. The vulnerability is classified under CWE-134 which specifically addresses the use of externally-controlled format strings, a well-known security pattern that has been exploited in numerous high-profile attacks.
The operational impact of this vulnerability is severe and directly relates to the privilege escalation capabilities it provides. An attacker with a super-admin profile and CLI access can leverage this flaw to execute arbitrary code or commands on the affected system. This represents a complete compromise of the device's security posture since the attacker already possesses administrative privileges, but the format string vulnerability allows them to escalate their capabilities beyond what would normally be possible. The local privileged attacker can manipulate the format string parameters to overwrite memory locations, execute shellcode, or redirect program execution flow. This type of vulnerability is particularly dangerous in network security devices like FortiOS firewalls because it can lead to complete network compromise, data exfiltration, or the establishment of persistent backdoors within the organization's security infrastructure.
The attack vector for this vulnerability requires an attacker to already possess a super-admin profile and command line interface access, which means the initial compromise typically occurs through other attack vectors such as credential theft, phishing attacks, or exploitation of other vulnerabilities. Once inside the system with administrative privileges, the attacker can craft specially formatted requests that trigger the vulnerable format string handling code. This attack pattern aligns with the ATT&CK framework's privilege escalation techniques, specifically targeting command and control operations where adversaries seek to maintain persistent access and expand their capabilities within the compromised environment. The vulnerability demonstrates the importance of proper input validation and the dangers of allowing user-controlled data to influence program execution flows.
Organizations should immediately prioritize patching all affected FortiOS versions to mitigate this vulnerability. The recommended mitigation strategy involves upgrading to the latest stable versions of FortiOS that contain the necessary security fixes for the format string vulnerability. Additionally, network administrators should implement strict access controls and monitoring for CLI activities, particularly for super-admin accounts. Security teams should conduct comprehensive vulnerability assessments to identify all affected devices and ensure proper patch management procedures are in place. The implementation of network segmentation and least privilege access principles can help limit the potential impact if an attacker does manage to exploit this vulnerability. Regular security audits and penetration testing should be conducted to identify similar weaknesses in other network security devices and applications within the organization's infrastructure.