CVE-2019-5587 in FortiOS
Summary
by MITRE
Lack of root file system integrity checking in Fortinet FortiOS VM application images all versions below 6.0.5 may allow attacker to implant malicious programs into the installing image by reassembling the image through specific methods.
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Analysis
by VulDB Data Team • 09/28/2023
The vulnerability identified as CVE-2019-5587 represents a critical security flaw in Fortinet FortiOS VM application images affecting all versions prior to 6.0.5. This weakness stems from insufficient integrity verification mechanisms during the installation process of the FortiOS virtual machine images, creating a pathway for malicious actors to compromise the system through image manipulation techniques. The vulnerability specifically targets the root file system integrity checking functionality that should normally validate the authenticity and integrity of the installation components before they are deployed.
The technical implementation of this flaw allows attackers to exploit the absence of proper cryptographic verification or checksum validation during the image reassembly process. When FortiOS VM images are installed, the system fails to perform adequate integrity checks that would normally detect unauthorized modifications to the root file system components. This weakness enables adversaries to substitute legitimate files with malicious counterparts without detection, effectively creating a backdoor installation mechanism. The vulnerability is particularly concerning because it operates at the foundational level of the operating system, allowing for deep persistence within the network security infrastructure.
The operational impact of this vulnerability extends beyond simple code injection, as it provides attackers with the capability to establish persistent access points within enterprise network security environments. Once an attacker successfully implants malicious code into the FortiOS VM image, they can maintain long-term access to the network infrastructure while evading traditional detection mechanisms. This vulnerability directly affects the security posture of organizations relying on Fortinet firewalls, as it undermines the fundamental trust in the integrity of their network security appliances. The attack vector typically involves sophisticated image manipulation techniques that require understanding of the FortiOS installation process and file system structure.
Organizations utilizing affected Fortinet FortiOS VM versions face significant risk of compromise, as this vulnerability can be exploited by attackers with moderate technical expertise to gain unauthorized access to network security controls. The vulnerability aligns with CWE-1037, which addresses insufficient integrity checking of critical resources, and can be mapped to ATT&CK technique T1490, representing Data Destruction, and T1059, representing Command and Scripting Interpreter, as attackers can leverage this vulnerability to establish persistent command execution capabilities. Remediation efforts should focus on immediate deployment of Fortinet FortiOS version 6.0.5 or later, which includes enhanced image integrity verification mechanisms. Additionally, organizations should implement comprehensive monitoring of system image integrity, conduct regular security assessments of network infrastructure, and establish secure software supply chain practices to prevent similar vulnerabilities from emerging in other security components.