Critical Path Traversal Vulnerability in FortiSIEM (CVE-2023-40714) Allows Privilege Escalation

A critical vulnerability (CVE-2023-40714) affecting multiple versions of Fortinet’s FortiSIEM security information and event management solution has been identified, allowing authenticated attackers to escalate privileges through path traversal attacks. The flaw, discovered internally by Fortinet’s ETAC team, carries a CVSSv3 score of 9.7 and affects versions from 6.4.0 through 7.0.0.

Executive Summary for Security Leadership

The vulnerability enables authenticated low-privileged users to perform arbitrary file overwrites through crafted HTTP requests to the FortiSIEM GUI file upload component. Successful exploitation could allow attackers to replace system files and gain super-admin privileges. Fortinet has released patched versions across all affected product lines, with immediate patching recommended as the primary mitigation strategy.

Affected Products: FortiSIEM versions 6.4.0-6.4.2, 6.5.0-6.5.1, 6.6.0-6.6.3, 6.7.0-6.7.3, and 7.0.0
Vulnerability Type: Relative Path Traversal (CWE-23)
Impact: Privilege escalation to super-admin level
Discovery: Internally by Fortinet ETAC team member Lance Yeaw
Patch Status: Fixed in 7.0.1+, 6.7.4+, 6.6.4+, 6.5.2+, and 6.4.3+

Technical Analysis

The vulnerability stems from insufficient validation of file paths in the FortiSIEM GUI file upload component. Attackers can craft HTTP requests containing relative path sequences (e.g., “../”) to write files outside the intended directory structure. This path traversal flaw enables authenticated users with minimal privileges to overwrite critical system files, potentially gaining full administrative control of the FortiSIEM instance.

Fortinet’s advisory FG-IR-23-085 confirms the vulnerability affects the web-based management interface across all listed versions. The attack requires authentication but does not require high privileges, making it particularly dangerous in environments where multiple users have access to FortiSIEM’s web interface.

Detection and Mitigation

Organizations should immediately check their FortiSIEM version against the affected list and upgrade to the latest patched version. For environments where immediate patching isn’t feasible, monitoring for unusual file modification activity in the FortiSIEM filesystem is recommended. Tenable has released Plugin ID 197604 to help identify vulnerable installations.

Fortinet has not disclosed specific workarounds, emphasizing that patching is the only complete solution. Security teams should review logs for unexpected file upload activities, particularly those involving path manipulation patterns in HTTP requests to the FortiSIEM web interface.

Relevance to Security Professionals

This vulnerability presents multiple concerns for security teams. For defensive operations, the flaw could allow attackers to manipulate security event data or disable monitoring capabilities. Offensive security professionals should note that this vulnerability requires authentication, making it most relevant in post-exploitation scenarios after initial access is achieved.

The critical nature of this vulnerability is underscored by its inclusion in advisories from multiple national cybersecurity organizations, including FinCSIRT and the U.S. Department of Health and Human Services HC3 team. The broad impact across multiple FortiSIEM versions makes this a high-priority remediation item for all affected organizations.

Conclusion

CVE-2023-40714 represents a serious threat to organizations using vulnerable FortiSIEM versions, with the potential for complete system compromise through privilege escalation. The widespread deployment of FortiSIEM in enterprise environments and its role in security monitoring make timely patching essential. Security teams should prioritize this update and monitor for any indicators of attempted exploitation.