CVE-2019-16149 in FortiClientEMS
Summary
by MITRE • 03/28/2025
An Improper Neutralization of Input During Web Page Generation in FortiClientEMS version 6.2.0 may allow a remote attacker to execute unauthorized code by injecting malicious payload in the user profile of a FortiClient instance being managed by the vulnerable system.
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Analysis
by VulDB Data Team • 07/16/2025
The vulnerability identified as CVE-2019-16149 represents a critical security flaw in FortiClientEMS version 6.2.0 that stems from improper input neutralization during web page generation processes. This weakness creates a pathway for remote code execution attacks through the manipulation of user profile data within the managed FortiClient instances. The vulnerability specifically targets the web interface component of the FortiClient Endpoint Management System, which serves as the central management console for deploying and monitoring FortiClient security agents across enterprise networks. The flaw exists in how the system processes and renders user profile information when generating web pages for display in the management interface, creating an environment where malicious payloads can be injected and subsequently executed with the privileges of the web application.
The technical implementation of this vulnerability aligns with CWE-79, which describes improper neutralization of input during web page generation, commonly known as cross-site scripting or XSS vulnerabilities. However, this particular instance demonstrates a more severe variant where the XSS payload can be crafted to execute arbitrary code rather than merely deface web pages or steal session cookies. The attack vector requires a remote attacker to inject malicious code into user profile fields that are then processed by the web generation engine. When the vulnerable system renders these profiles in web pages, the injected code executes in the context of the web server, potentially allowing attackers to gain full control over the management system. The vulnerability is particularly dangerous because FortiClientEMS serves as a centralized management platform for endpoint security, making it an attractive target for attackers seeking to compromise entire enterprise networks through a single point of entry.
The operational impact of this vulnerability extends beyond simple code execution, as it fundamentally undermines the security posture of organizations relying on FortiClientEMS for endpoint management. Successful exploitation could enable attackers to manipulate security policies, deploy malicious software across managed endpoints, modify user access controls, and potentially establish persistent backdoors within the network infrastructure. The remote nature of the attack means that adversaries do not require physical access to the network or administrative privileges to exploit this vulnerability, making it particularly concerning for organizations with distributed deployments. The vulnerability also affects the integrity and confidentiality of sensitive data stored within the management system, as attackers could potentially access or modify user profiles, device configurations, and security policies that control the behavior of endpoint agents. According to ATT&CK framework, this vulnerability maps to techniques involving command and control communication and privilege escalation, as the successful exploitation allows attackers to execute arbitrary commands with elevated privileges.
Organizations affected by CVE-2019-16149 should implement immediate mitigations including applying the vendor-provided security patches and updates, implementing network segmentation to limit access to the FortiClientEMS management interface, and monitoring for suspicious activity in user profile modifications. The vulnerability demonstrates the critical importance of input validation and output encoding in web applications, particularly those handling user-generated content in management interfaces. Security teams should also consider implementing web application firewalls to detect and block suspicious payloads targeting this specific vulnerability, while conducting thorough audits of user profile data to identify any potential exploitation attempts. The remediation process should include comprehensive testing of patched systems to ensure that the vulnerability has been properly addressed without introducing regressions in functionality. Additionally, organizations should review their incident response procedures to ensure readiness for potential exploitation of this vulnerability, as the remote code execution capability provides attackers with significant operational advantages in targeting enterprise infrastructure.