Fortinet FortiOS / FortiProxy / FortiPAM Format String Vulnerability (CVE-2024-23113) Remote Code Execution (RCE) Analysis and Mitigation Guide
Executive & SecOps Summary
SECOPS ASSESSMENTFortiOS (7.0.0~7.0.13, 7.2.0~7.2.6, 7.4.0~7.4.2), FortiProxy (7.0.0~7.0.14, 7.2.0~7.2.8, 7.4.0~7.4.2), FortiPAM, and FortiSwitchManager specific versions
Unauthenticated remote attackers can execute unauthorized code or commands with root privileges via specially crafted packets
Upgrade to the official patched versions immediately, or disable the FGFM (FortiGate Federation Management) service on interfaces as a temporary workaround
Affected Products & Version Scope
Remediation & Live Workaround Commands
PATCH & WORKAROUND1. Official Patch & Version Upgrade Commands
The primary remediation is upgrading to the patched firmware versions (FortiOS 7.4.3+, 7.2.7+, 7.0.14+). Use the following CLI commands to verify and upgrade your system:
# Check current FortiOS version
get system status
# Example: Upgrade firmware via TFTP server
# Ensure you select the appropriate patched image for your hardware model
execute restore image tftp FGT_60F-v7.4.3.out 192.168.1.992. Temporary Workaround & Hardening Configuration
If patching cannot be applied immediately, disable FGFM access on all public-facing interfaces to mitigate the attack vector. Use the following configuration to remove 'fgfm' from the allowed access list:
# Disable fgfm service on the external interface (e.g., port1)
config system interface
edit 'port1'
set allowaccess ping https ssh
next
end3. Log Audit & IoC Verification Commands
Monitor system logs for unexpected crashes of the fgfmd daemon and inspect active connections on TCP port 541 to identify potential exploitation attempts.
# Check system crash logs for fgfmd daemon failures
show system crashlog
# Inspect active sessions on the FGFM port (TCP 541)
diagnose sys session filter dport 541
diagnose sys session listStop Exposing VPN Ports to the Internet — Switch to Zero-Trust Access
Eliminate public-facing VPN concentrators and firewall management ports with identity-first Zero-Trust Network Access.
Technical Root Cause & Exploitation Mechanics
1. Vulnerability Overview & Root Cause
This vulnerability (CVE-2024-23113) is an externally-controlled format string vulnerability (CWE-134) residing in the FortiGate Federation Management (FGFM) daemon (fgfmd) of Fortinet products. The root cause is the unsafe handling of user-supplied input within format string functions (such as printf-family or logging functions) without proper validation. An attacker can inject format specifiers (e.g., %x, %s, %n) into the input stream to read from or write to arbitrary memory locations.
2. Exploitation Mechanics & Attack Scenario
An unauthenticated attacker targets the FGFM service, which typically listens on TCP port 541. By sending specially crafted network packets containing malicious format string specifiers to the exposed FGFM port, the attacker triggers the vulnerability during packet parsing by the fgfmd daemon. This allows the attacker to overwrite critical memory structures, hijack the control flow of the process, and execute arbitrary shellcode with administrative (root) privileges.
3. Infrastructure & Business Impact
With a CVSS score of 9.8 (Critical) and its inclusion in CISA's Known Exploited Vulnerabilities (KEV) catalog, this vulnerability poses an immediate threat to enterprise networks. Because FortiGate firewalls and VPN gateways serve as perimeter security boundaries, successful exploitation grants attackers initial access to the internal network. This can lead to complete infrastructure compromise, data exfiltration, and subsequent ransomware deployment.
Official Vendor Advisories & References
A use of externally-controlled format string in Fortinet FortiOS versions 7.4.0 through 7.4.2, 7.2.0 through 7.2.6, 7.0.0 through 7.0.13, FortiProxy versions 7.4.0 through 7.4.2, 7.2.0 through 7.2.8, 7.0.0 through 7.0.14, FortiPAM versions 1.2.0, 1.1.0 through 1.1.2, 1.0.0 through 1.0.3, FortiSwitchManager versions 7.2.0 through 7.2.3, 7.0.0 through 7.0.3 allows attacker to execute unauthorized code or commands via specially crafted packets.
Frequently Asked SecOps Questions (CVE-2024-23113)
FAQQ1. How critical is CVE-2024-23113 and is it actively exploited in the wild?
CVE-2024-23113 is rated CVSS 9.8 (CRITICAL) with a 30-day EPSS exploitation probability of 61.7%. It is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, requiring immediate emergency remediation.
Q2. Which vendors and products are affected by CVE-2024-23113?
Primary impacted vendors include fortinet across fortios, fortiproxy, fortipam, fortiswitchmanager. Scope summary: FortiOS 7.4.0 to 7.4.2, 7.2.0 to 7.2.6, 7.0.0 to 7.0.13 / FortiProxy 7.4.0 to 7.4.2, 7.2.0 to 7.2.8, 7.0.0 to 7.0.14 / FortiPAM 1.2.0, 1.1.0 to 1.1.2, 1.0.0 to 1.0.3 / FortiSwitchManager 7.2.0 to 7.2.3, 7.0.0 to 7.0.3
Q3. What temporary mitigations or workarounds exist for CVE-2024-23113 before patching?
[Mitigation] Upgrade to the official patched versions immediately, or disable the FGFM (FortiGate Federation Management) service on interfaces as a temporary workaround Follow the CLI remediation commands and interactive SecOps checklist on this page to restrict exposure prior to your maintenance window.
Generate an Internal Engineering Notice or CISO Report for CVE-2024-23113
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🔗 Related Advisories in Similar Stack (fortinet)
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