Threat actors have recently exploited a vulnerability in Fortinet Forticlient EMS, identified as CVE-2023-48788, to infiltrate targeted systems and install unauthorized Remote Monitoring and Management (RMM) tools as well as PowerShell backdoors. This vulnerability, with a severity rating of 9.8 (Critical), allows unauthenticated users to execute commands with SYSTEM privileges via specially crafted messages. Upon exploiting an external inbound network connection, the threat actors initiate downloads and executions of malicious payloads, leveraging SQL injection to gain SYSTEM-level access and execute commands.
Fortinet addressed the vulnerability in March 2024; however, exploitation remains a concern for systems running unpatched versions of Forticlient EMS. Horizon3 researchers published a comprehensive report detailing the exploitation process, which involves threat actors attempting to establish connections with the FCMdaemon process of the Forticlient EMS application. Once successful, the attackers exploit SQL injection to enable xp_cmdshell and execute commands through cmd.exe, thereby gaining elevated privileges for further malicious activities.
In their exploitation strategy, the threat actors utilize PowerShell Invoke-WebRequest cmdlets to download Windows installer files from malicious IP addresses. These MSI installers often contain RMM tools, which, if successfully installed, grant the attackers persistent access to the compromised systems. Notably, the attackers can deploy these tools using the msiexec.exe process, facilitating their remote monitoring and management capabilities.
To mitigate the risk posed by this vulnerability, Fortinet advises users to upgrade their Forticlient EMS applications to the latest version and remain vigilant for unauthorized network connections and suspicious PowerShell processes. Additionally, implementing allowlists or blocklists to prevent unauthorized RMM tool installations can further enhance security measures. Heightened awareness and proactive patching are crucial steps in defending against such exploits and safeguarding against unauthorized access to sensitive systems and data.
