CVE-2024-47574: Fortinet FortiClient Auth Bypass Vulnerability

CVE-2024-47574 Overview

CVE-2024-47574 is an authentication bypass vulnerability affecting Fortinet FortiClientWindows that allows a low-privilege attacker to execute arbitrary code with elevated privileges. The vulnerability exists due to improper authentication controls when handling named pipe communications, enabling attackers to spoof messages and bypass security restrictions.

This vulnerability is classified under CWE-288 (Authentication Bypass Using an Alternate Path or Channel) and CWE-306 (Missing Authentication for Critical Function), indicating fundamental flaws in the authentication architecture of the affected software.

Critical Impact

Low-privilege attackers can escalate to high privileges and execute arbitrary code on vulnerable FortiClientWindows installations through spoofed named pipe messages.

Affected Products

• Fortinet FortiClientWindows version 7.4.0
• Fortinet FortiClientWindows versions 7.2.0 through 7.2.4
• Fortinet FortiClientWindows versions 7.0.0 through 7.0.12
• Fortinet FortiClientWindows versions 6.4.0 through 6.4.10

Discovery Timeline

• 2024-11-13 - CVE-2024-47574 published to NVD
• 2025-01-21 - Last updated in NVD database

Technical Details for CVE-2024-47574

Vulnerability Analysis

This authentication bypass vulnerability targets the inter-process communication (IPC) mechanism in FortiClientWindows. The software utilizes named pipes for communication between different components, but fails to properly authenticate the source of incoming messages. An attacker with local access and low privileges can exploit this weakness by crafting spoofed named pipe messages that appear to originate from trusted system components.

The exploitation path leverages the trust relationship between FortiClient components. When a high-privilege service accepts messages from a named pipe without verifying the sender's identity or integrity of the request, it creates an opportunity for privilege escalation. The attacker can inject malicious commands or payloads that execute in the context of the privileged service.

Root Cause

The root cause of CVE-2024-47574 stems from missing authentication for critical functions (CWE-306) combined with the availability of alternate communication channels that bypass standard security controls (CWE-288). The FortiClientWindows service does not adequately verify the authenticity of named pipe messages before processing them, allowing any local user to communicate with privileged components.

Named pipes in Windows provide a mechanism for IPC, but security depends on proper implementation of access controls and message validation. In this case, the FortiClient service accepts and processes messages from the named pipe without sufficient verification of the caller's identity or privilege level.

Attack Vector

The attack vector is local, requiring the attacker to have low-privilege access to a system running a vulnerable version of FortiClientWindows. The exploitation does not require user interaction, making it particularly dangerous in environments where multiple users share access to systems or where malware has gained initial low-privilege access.

The attacker connects to the FortiClient named pipe and sends specially crafted messages that impersonate legitimate high-privilege requests. Because the service lacks proper authentication checks, these spoofed messages are processed with elevated privileges, allowing the attacker to execute arbitrary code in the security context of the FortiClient service.

The vulnerability mechanism involves sending crafted messages through the FortiClientWindows named pipe communication channel. Since the service fails to properly authenticate message sources, attackers can impersonate trusted components and escalate privileges. For detailed technical information, refer to the Fortinet PSIRT Advisory FG-IR-24-199.

Detection Methods for CVE-2024-47574

Indicators of Compromise

• Unexpected processes or child processes spawned by FortiClient services with elevated privileges
• Anomalous named pipe connections to FortiClient communication channels from non-standard processes
• Unusual privilege escalation events associated with FortiClient executable paths
• Suspicious code execution events originating from FortiClient service context

Detection Strategies

• Monitor named pipe access patterns for connections from unexpected or untrusted processes
• Implement endpoint detection rules to identify privilege escalation attempts targeting FortiClient services
• Configure Windows Event Log monitoring for security events related to impersonation and privilege changes
• Deploy behavioral analysis to detect anomalous process chains involving FortiClient components

Monitoring Recommendations

• Enable detailed logging for named pipe operations on FortiClient systems
• Configure SentinelOne behavioral AI to monitor for privilege escalation attempts via IPC mechanisms
• Implement process ancestry tracking to detect suspicious child processes spawned by FortiClient services
• Monitor for unauthorized modifications to FortiClient configuration or executables

How to Mitigate CVE-2024-47574

Immediate Actions Required

• Upgrade FortiClientWindows to a patched version as specified in the Fortinet security advisory
• Audit systems for signs of exploitation before and after patching
• Restrict local user accounts and review access permissions on systems running FortiClient
• Enable enhanced endpoint monitoring on systems pending patch deployment

Patch Information

Fortinet has released security patches to address this vulnerability. Organizations should consult the Fortinet PSIRT Advisory FG-IR-24-199 for specific version remediation guidance and download the latest secure versions of FortiClientWindows.

Ensure all FortiClientWindows installations are updated to versions that address this authentication bypass:

• Upgrade from 7.4.0 to the latest patched release
• Upgrade from 7.2.x (versions 7.2.0-7.2.4) to a patched version
• Upgrade from 7.0.x (versions 7.0.0-7.0.12) to a patched version
• Upgrade from 6.4.x (versions 6.4.0-6.4.10) to a patched version

Workarounds

• Limit local user access on systems running FortiClientWindows to reduce attack surface
• Implement application whitelisting to prevent unauthorized code execution
• Deploy endpoint protection solutions with behavioral analysis capabilities
• Consider temporary isolation of critical systems until patches can be applied

# Verify FortiClient version on Windows systems
# Run in PowerShell to check installed FortiClient version
Get-WmiObject -Class Win32_Product | Where-Object {$_.Name -like "*FortiClient*"} | Select-Object Name, Version

# Monitor FortiClient related processes for suspicious activity
Get-Process | Where-Object {$_.ProcessName -like "*FortiClient*"} | Format-Table ProcessName, Id, StartTime