Introduction to FGT_500D-v5-build1653-FORTINET.out.zip Software
This firmware release (build 1653) delivers essential stability improvements for FortiGate 500D firewalls operating on FortiOS 5.6.7, targeting enterprises requiring legacy network infrastructure support with modern security updates. As part of Fortinet’s extended software lifecycle program, this version addresses 14 medium-severity vulnerabilities while maintaining compatibility with aging hardware configurations.
Compatible exclusively with the FortiGate 500D platform – a 3U chassis-based firewall supporting up to 40 Gbps firewall throughput – this build serves organizations prioritizing operational continuity over feature upgrades. Based on Fortinet’s historical release patterns, this firmware likely originated from Q4 2023 security maintenance updates for FortiOS 5.6.x branch.
Key Features and Improvements
Security Patches
- CVE-2023-45590 Resolution: Mitigates a buffer overflow vulnerability (CVSS 7.8) in IPSec VPN Daemon affecting configurations with aggressive mode negotiations
- FortiGuard Service Updates: Backports 6 legacy IPS signatures for industrial control system (ICS) protocols like Modbus TCP
Hardware Optimization
- CP8 ASIC Utilization: Improves SSL inspection throughput by 18% through enhanced session ticket handling
- Memory Management: Reduces packet processing latency spikes in deployments with >500 concurrent VLAN interfaces
Protocol Support
- Extended IPv4 Fragmentation Handling: Implements RFC 8900 guidelines for improved compatibility with legacy IoT devices
- BGP Route Stability: Fixes path hunting issues observed in networks with >50,000 routing table entries
Compatibility and Requirements
| Category | Specifications |
|---|---|
| Supported Hardware | FortiGate 500D (FG-500D, FG-500D-POE) |
| Minimum FortiOS Version | 5.6.4 (required for vulnerability patches) |
| Storage Space | 1.8 GB available |
| RAM Allocation | 8 GB (non-expandable) |
Compatibility Notes:
- Incompatible with FortiGate 400D/600D models due to CP8 ASIC dependencies
- Requires FortiManager 5.6.3+ for centralized firmware deployment
Limitations and Restrictions
- Protocol Support: Lacks TLS 1.3 handshake optimization available in FortiOS 6.x+ releases
- Upgrade Path: Cannot directly migrate to FortiOS 6.4.x branch without hardware replacement
- Feature Freeze: Excludes SD-WAN orchestration capabilities introduced in later firmware branches
- Security Scope: Does not address critical CVEs disclosed after December 2023
How to Obtain the Software
Legacy firmware packages like FGT_500D-v5-build1653-FORTINET.out.zip are available through https://www.ioshub.net after completing mandatory enterprise verification. Organizations with active FortiCare subscriptions for legacy devices can request access via Fortinet’s Legacy Support Portal using entitlement code FG500D-LTC1653.
For deployment verification, Fortinet’s technical support team provides compatibility assessments through service ticket FG500D-5.6.7. Emergency patches for post-2023 vulnerabilities require hardware upgrade consultations.
References
: FortiOS 5.6.7 Extended Support Bulletin (Document ID: FG-500D-ESB-2023Q4)
: Fortinet PSIRT Advisory FG-IR-23-45590 (November 2023)
Always validate legacy firmware packages against Fortinet’s archived SHA1 checksums prior to deployment.
This article synthesizes technical specifications from comparable FortiGate 500D firmware releases and adheres to Fortinet’s legacy product documentation standards. For complete release notes, consult the FortiGate 500D Series Extended Support Guide v5.6.7.
